The Itchy Dog: Sources

Full references for the book by Steve Pelton, DVM. 483 sources, listed by chapter in the same order as the small numbers in the text.

Each entry has the authors, title, journal or publisher and year, plus a DOI or link when there is one. To read a paper, open the DOI link or search its title in PubMed. Some papers sit behind a paywall; the abstract is usually free, and your vet or a library can often get the rest.

Chapter 1: Lick, lick, lick

  1. Nationwide. "Chronic conditions dominate this year's list of most common and expensive pet health problems." Press release, March 2026. https://news.nationwide.com/chronic-conditions-dominate-this-years-list-of-most-common-and-expensive-pet-health-problems/ (skin allergies the top claim for the 15th year running, more than 3.3 million claims)
  2. MSD Animal Health. Global canine itch survey of 1,710 dog owners and 1,413 veterinarians in 11 countries. June 2026. https://www.msd-animal-health.com/news-and-insights/featured-stories/itchsurvey/ (industry-sponsored survey)
  3. Elanco Animal Health. America's Itchy Dogs report. 2025. https://assets.elanco.com/0cec44ed-3eaa-0009-2029-666567e7e4de/33474a48-bac3-4fc4-b7fc-3589b88560fb/ElancoItchyDogsReportFINAL.pdf (industry-sponsored survey)
  4. Shaw SC, Wood JLN, Freeman J, Littlewood JD, Hannant D. Estimation of heritability of atopic dermatitis in Labrador and Golden Retrievers. Am J Vet Res. 2004;65(7):1014-1020. PMID 15281664. (heritability estimate 0.47, from 32 litters)
  5. Anderegg WRL, Abatzoglou JT, Anderegg LDL, Bielory L, Kinney PL, Ziska L. Anthropogenic climate change is worsening North American pollen seasons. Proc Natl Acad Sci USA. 2021;118(7):e2013284118. doi:10.1073/pnas.2013284118 (seasons start about 20 days earlier and carry about 21% more pollen, 1990 to 2018)
  6. Coyner K, Schick A. Hair and saliva analysis fails to accurately identify atopic dogs or differentiate real and fake samples. Vet Dermatol. 2019;30(1). doi:10.1111/vde.12716. PMID 30680834.
  7. See Chapter 6, references on flea allergy dermatitis.
  8. Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Vet Res. 2016;12:9. doi:10.1186/s12917-016-0633-8 (pooled provocation-confirmed cases from studies published 1985 to 2015)
  9. Olivry T, Mueller RS, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (1): duration of elimination diets. BMC Vet Res. 2015;11:225. doi:10.1186/s12917-015-0541-3
  10. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5
  11. Author's clinic pricing, Cypress, Texas, 2026; Hearthstone Animal Clinic, Cypress dog-allergies page. (rough estimates for a 55-pound dog; local prices vary)
  12. Santoro D, Marsella R, Pucheu-Haston CM, et al. Review: Pathogenesis of canine atopic dermatitis: skin barrier and host-micro-organism interaction. Vet Dermatol. 2015;26(2):84-e25.
  13. Gonzales AJ, Humphrey WR, Messamore JE, et al. Interleukin-31: its role in canine pruritus and naturally occurring canine atopic dermatitis. Vet Dermatol. 2013;24(1):48-e12. PMID 23331679.
  14. Olivry T, DeBoer DJ, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6
  15. Banfield Pet Hospital. State of Pet Health 2018 Report (allergy edition; 2008 to 2017 data on more than 3 million pets). https://banfield.com/about-banfield/newsroom/press-releases/2018/2018-state-of-pet-health-report-explores-pet-aller
  16. Trupanion. "Itchy and Sneezy: More Pets are Seeking Allergy Relief." Press release, March 25, 2025. https://investors.trupanion.com/news/Press-Releases/news-details/2025/Itchy-and-Sneezy-More-Pets-are-Seeking-Allergy-Relief-2025-yG3z-9yJvj/default.aspx
  17. Hakanen E, Lehtimäki J, Salmela E, et al. Urban environment predisposes dogs and their owners to allergic symptoms. Sci Rep. 2018;8:1585. doi:10.1038/s41598-018-19953-3

Chapter 2: What itch actually is

  1. Ikoma A, Steinhoff M, Ständer S, Yosipovitch G, Schmelz M. The neurobiology of itch. Nat Rev Neurosci. 2006;7(7):535-547. (itch as its own sensation, histamine-independent itch fibers, and pain suppressing itch)
  2. Santoro D, Marsella R, Pucheu-Haston CM, Eisenschenk MNC, Nuttall T, Bizikova P. Review: Pathogenesis of canine atopic dermatitis: skin barrier and host-micro-organism interaction. Vet Dermatol. 2015;26(2):84-e25.
  3. Mack MR, Kim BS. The itch-scratch cycle: a neuroimmune perspective. Trends Immunol. 2018;39(12):980-991. PMID 30471983. (human and mouse research, applied to dogs by analogy)
  4. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5
  5. Olivry T, DeBoer DJ, Favrot C, Jackson HA, Mueller RS, Nuttall T, Prélaud P. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6
  6. Drechsler Y, Dong C, Clark DE, Kaur G. Canine atopic dermatitis: prevalence, impact, and management strategies. Vet Med (Auckl). 2024;15:15-29. doi:10.2147/VMRR.S412570
  7. Gonzales AJ, Humphrey WR, Messamore JE, et al. Interleukin-31: its role in canine pruritus and naturally occurring canine atopic dermatitis. Vet Dermatol. 2013;24(1):48-e12. PMID 23331679. (serum IL-31 detected in 57% of dogs with naturally occurring atopic dermatitis and not in normal dogs; injection study in laboratory Beagles)
  8. Gonzales AJ, Bowman JW, Fici GJ, et al. Oclacitinib (APOQUEL) is a novel Janus kinase inhibitor with activity against cytokines involved in allergy. J Vet Pharmacol Ther. 2014;37(4):317-324. doi:10.1111/jvp.12101
  9. Michels GM, Ramsey DS, Walsh KF, et al. A blinded, randomized, placebo-controlled, dose determination trial of lokivetmab (ZTS-00103289), a caninized, anti-canine IL-31 monoclonal antibody in client owned dogs with atopic dermatitis. Vet Dermatol. 2016;27(6):478-e129. (211 client-owned dogs at 15 referral clinics; three doses compared with placebo)
  10. Carr MN, Torres SMF, Koch SN, Reiter LV. Investigation of the pruritogenic effects of histamine, serotonin, tryptase, substance P and interleukin-2 in healthy dogs. Vet Dermatol. 2009;20(2):105-110.
  11. Hill PB, Lau P, Rybnicek J. Development of an owner-assessed scale to measure the severity of pruritus in dogs. Vet Dermatol. 2007;18(5):301-308.
  12. Jaeger K, Linek M, Power HT, Bettenay SV, Zabel S, Rosychuk RAW, Mueller RS. Breed and site predispositions of dogs with atopic dermatitis: a comparison of five locations in three continents. Vet Dermatol. 2010;21(1):119-123. (552 atopic dogs)
  13. Rybnicek J, Lau-Gillard P, Harvey R, Hill PB. Further validation of a pruritus severity scale for use in dogs. Vet Dermatol. 2009;20(2):115-122. (713 owners; 408 dogs with skin disease and 305 without; normal range 0 to 1.9)
  14. Lavery MJ, Stull C, Kinney MO, Yosipovitch G. Nocturnal pruritus: the battle for a peaceful night's sleep. Int J Mol Sci. 2016;17(3):425. doi:10.3390/ijms17030425 (human data)
  15. Nuttall T, McEwan N. Objective measurement of pruritus in dogs: a preliminary study using activity monitors. Vet Dermatol. 2006;17(5):348-351.

Chapter 3: The leaky brick wall

  1. Eisenschenk MC, Hensel P, Saridomichelakis MN, Tamamoto-Mochizuki C, Pucheu-Haston CM, Santoro D. Introduction to the ICADA 2023 canine atopic dermatitis pathogenesis review articles and updated definition. Vet Dermatol. 2024;35(1). PMID 38095285. (the updated ICADA definition of canine atopic dermatitis)
  2. Drechsler Y, Dong C, Clark DE, Kaur G. Canine atopic dermatitis: prevalence, impact, and management strategies. Vet Med (Auckl). 2024;15:15-29. doi:10.2147/VMRR.S412570
  3. Santoro D, Marsella R, Pucheu-Haston CM, Eisenschenk MNC, Nuttall T, Bizikova P. Review: Pathogenesis of canine atopic dermatitis: skin barrier and host-micro-organism interaction. Vet Dermatol. 2015;26(2):84-e25.
  4. Santoro D, et al. Update on the skin barrier, cutaneous microbiome and host defence peptides in canine atopic dermatitis (ICADA). Vet Dermatol. 2024;35(1) (published online 2023).
  5. Reiter LV, Torres SMF, Wertz PW. Characterization and quantification of ceramides in the nonlesional skin of canine patients with atopic dermatitis compared with controls. Vet Dermatol. 2009;20(4):260-266.
  6. Hightower K, Marsella R, Flynn-Lurie A. Effects of age and allergen exposure on transepidermal water loss in a house dust mite-sensitized beagle model of atopic dermatitis. Vet Dermatol. 2010;21(1):89-96.
  7. Olivry T, Wofford J, Paps JS, Dunston SM. Stratum corneum removal facilitates experimental sensitization to mite allergens in atopic dogs. Vet Dermatol. 2011;22(2):188-196. (tape-stripped skin sensitized to dust mite allergen more easily than intact skin)
  8. Chervet L, Galichet A, McLean WHI, et al. Missing C-terminal filaggrin expression, NFkappaB activation and hyperproliferation identify the dog as a putative model to study epidermal dysfunction in atopic dermatitis. Exp Dermatol. 2010;19(8):e343-e346.
  9. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5. PMID 26260508.
  10. Gonzales AJ, Humphrey WR, Messamore JE, et al. Interleukin-31: its role in canine pruritus and naturally occurring canine atopic dermatitis. Vet Dermatol. 2013;24(1):48-e12. PMID 23331679.
  11. Hensel P, et al. Update on the role of genetic factors, environmental factors and allergens in canine atopic dermatitis (ICADA). Vet Dermatol. 2024;35(1) (published online October 2023).
  12. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (8): storage mites in commercial pet foods. BMC Vet Res. 2019;15:385. doi:10.1186/s12917-019-2102-7
  13. Trupanion. "Itchy and Sneezy: More Pets are Seeking Allergy Relief." Press release, March 25, 2025. https://investors.trupanion.com/news/Press-Releases/news-details/2025/Itchy-and-Sneezy-More-Pets-are-Seeking-Allergy-Relief-2025-yG3z-9yJvj/default.aspx (seasonal claim peaks and breeds with the most allergy claims)
  14. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (3): prevalence of cutaneous adverse food reactions in dogs and cats. BMC Vet Res. 2017;13:51. doi:10.1186/s12917-017-0973-z
  15. Jaeger K, Linek M, Power HT, Bettenay SV, Zabel S, Rosychuk RAW, Mueller RS. Breed and site predispositions of dogs with atopic dermatitis: a comparison of five locations in three continents. Vet Dermatol. 2010;21(1):119-123. (552 dogs at sites in Australia, Germany and the USA; paws 62%, belly 51%, ears 48%, face 39%)
  16. Merck Veterinary Manual (professional version). Atopic dermatitis in dogs. https://www.merckvetmanual.com/integumentary-system/atopic-dermatitis/atopic-dermatitis-in-dogs (accessed 2026-10-06)
  17. American Kennel Club. "Why is my dog's fur changing color?" AKC Expert Advice. https://www.akc.org/expert-advice/health/why-is-my-dogs-fur-changing-color/ (porphyrin staining from saliva and tears)
  18. Favrot C, Steffan J, Seewald W, Picco F. A prospective study on the clinical features of chronic canine atopic dermatitis and its diagnosis. Vet Dermatol. 2010;21(1):23-31. (5 of 8 criteria: sensitivity 85%, specificity 79%)
  19. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (7): signalment and cutaneous manifestations of dogs and cats with adverse food reactions. BMC Vet Res. 2019;15:140. doi:10.1186/s12917-019-1880-2. PMCID PMC6507158. (age of onset ranged from under 1 year to 13 years)
  20. Shaw SC, Wood JLN, Freeman J, Littlewood JD, Hannant D. Estimation of heritability of atopic dermatitis in Labrador and Golden Retrievers. Am J Vet Res. 2004;65(7):1014-1020. PMID 15281664. (heritability 0.47)
  21. Nødtvedt A, Egenvall A, Bergvall K, Hedhammar Å. Incidence of and risk factors for atopic dermatitis in a Swedish population of insured dogs. Vet Rec. 2006;159(8):241-246. PMID 16921013. (rates per 1,000 dog-years at risk, 1995 to 2002)
  22. Olivry T, DeBoer DJ, Favrot C, Jackson HA, Mueller RS, Nuttall T, Prélaud P. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6

Chapter 4: The itch bucket

  1. Marsella R, Sousa CA. The ACVD task force on canine atopic dermatitis (XIII): threshold phenomenon and summation of effects. Vet Immunol Immunopathol. 2001;81(3-4):251-253.
  2. Olivry T, DeBoer DJ, Favrot C, Jackson HA, Mueller RS, Nuttall T, Prélaud P; International Committee on Allergic Diseases of Animals (ICADA). Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6 (flare factors: fleas, staph and Malassezia infections, food and environmental allergens; acute vs. chronic management)
  3. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5. PMID 26260508. Also: Hensel P, et al. Update on the role of genetic factors, environmental factors and allergens in canine atopic dermatitis (ICADA). Vet Dermatol. 2024;35(1) (published online October 2023).
  4. Trupanion. "Itchy and Sneezy: More Pets are Seeking Allergy Relief." Press release, March 25, 2025. https://investors.trupanion.com/news/Press-Releases/news-details/2025/Itchy-and-Sneezy-More-Pets-are-Seeking-Allergy-Relief-2025-yG3z-9yJvj/default.aspx (allergy claims peak in late spring and early fall)
  5. See Chapter 6, references on flea allergy dermatitis. Also Hensel P, et al. 2015 and Olivry T, et al. 2015 (references 3 and 2 above).
  6. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (3): prevalence of cutaneous adverse food reactions in dogs and cats. BMC Vet Res. 2017;13:51. doi:10.1186/s12917-017-0973-z (non-seasonal itch as a clue; food reactions in 9% to 50% of dogs diagnosed with atopic dermatitis across 22 articles; many food-allergic dogs are also atopic)
  7. Eisenschenk MC, Hensel P, Saridomichelakis MN, Tamamoto-Mochizuki C, Pucheu-Haston CM, Santoro D. Introduction to the ICADA 2023 canine atopic dermatitis pathogenesis review articles and updated definition. Vet Dermatol. 2024;35(1). PMID 38095285.
  8. Bradley CW, Morris DO, Rankin SC, et al. Longitudinal evaluation of the skin microbiome and association with microenvironment and treatment in canine atopic dermatitis. J Invest Dermatol. 2016;136(6):1182-1190.
  9. Favrot C, Steffan J, Seewald W, Picco F. A prospective study on the clinical features of chronic canine atopic dermatitis and its diagnosis. Vet Dermatol. 2010;21(1):23-31. (chronic or recurrent Malassezia infections as one of the criteria; 5 of 8 criteria: sensitivity 85%, specificity 79%)
  10. Santoro D, Marsella R, Pucheu-Haston CM, Eisenschenk MNC, Nuttall T, Bizikova P. Review: Pathogenesis of canine atopic dermatitis: skin barrier and host-micro-organism interaction. Vet Dermatol. 2015;26(2):84-e25. Also: Santoro D, et al. Update on the skin barrier, cutaneous microbiome and host defence peptides in canine atopic dermatitis (ICADA). Vet Dermatol. 2024;35(1).
  11. Olivry T, Wofford J, Paps JS, Dunston SM. Stratum corneum removal facilitates experimental sensitization to mite allergens in atopic dogs. Vet Dermatol. 2011;22(2):188-196.
  12. Mack MR, Kim BS. The itch-scratch cycle: a neuroimmune perspective. Trends Immunol. 2018;39(12):980-991. PMID 30471983.
  13. Ikoma A, Steinhoff M, Ständer S, Yosipovitch G, Schmelz M. The neurobiology of itch. Nat Rev Neurosci. 2006;7(7):535-547.
  14. Olivry T, Mueller RS, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (1): duration of elimination diets. BMC Vet Res. 2015;11:225. doi:10.1186/s12917-015-0541-3. See also Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (9): time to flare of cutaneous signs after a dietary challenge in dogs and cats with food allergies. BMC Vet Res. 2020;16:158. doi:10.1186/s12917-020-02379-3 (9 papers, 234 dogs)
  15. Author's clinic pricing, Cypress, Texas, 2026; Hearthstone Animal Clinic, Cypress dog-allergies page. (rough estimates for a dog of about 55 pounds; local prices vary)
  16. Author's clinical experience, Cypress, Texas. (Houston-area seasonal pattern: trees late winter to spring, grasses spring to summer, ragweed in fall)
  17. Anderegg WRL, Abatzoglou JT, Anderegg LDL, Bielory L, Kinney PL, Ziska L. Anthropogenic climate change is worsening North American pollen seasons. Proc Natl Acad Sci USA. 2021;118(7):e2013284118. doi:10.1073/pnas.2013284118 (seasons start about 20 days earlier and carry about 21% more pollen, 1990 to 2018)
  18. Ziska L, Knowlton K, Rogers C, et al. Recent warming by latitude associated with increased length of ragweed pollen season in central North America. Proc Natl Acad Sci USA. 2011;108(10):4248-4251. (13 to 27 days longer at latitudes above about 44 degrees N since 1995)
  19. European Medicines Agency. Cytopoint (lokivetmab): EPAR medicine overview and Summary of Product Characteristics (anti-drug antibodies are uncommon). https://www.ema.europa.eu/en/documents/overview/cytopoint-epar-medicine-overview_en.pdf. See also Today's Veterinary Practice, review of monoclonal antibodies in veterinary medicine (treatment-induced anti-drug antibodies in about 2.5% of treated dogs in Zoetis trials). Related trial: Michels GM, et al. A blinded, randomized, placebo-controlled trial of the safety of lokivetmab (ZTS-00103289), a caninized anti-canine IL-31 monoclonal antibody in client-owned dogs with atopic dermatitis. Vet Dermatol. 2016;27(6):505-e136 (245 dogs, 14 clinics).

Chapter 5: Why are there so many itchy dogs now?

  1. Nationwide. "Chronic conditions dominate this year's list of most common and expensive pet health problems." Press release, March 2026. https://news.nationwide.com/chronic-conditions-dominate-this-years-list-of-most-common-and-expensive-pet-health-problems/ (skin allergies the top claim for the 15th year running; more than 3.3 million claims from more than 1 million insured pets)
  2. Banfield Pet Hospital. 2018 State of Pet Health Report (pet allergies edition; 2008 to 2017 data on more than 3 million dogs and cats). https://banfield.com/about-banfield/newsroom/press-releases/2018/2018-state-of-pet-health-report-explores-pet-aller (environmental allergies up 30.7% and flea allergy up 12.5% in dogs). See also dvm360, "Flea, environmental allergies on the rise, says Banfield."
  3. Trupanion. "Itchy and Sneezy: More Pets are Seeking Allergy Relief." Press release, March 25, 2025. https://investors.trupanion.com/news/Press-Releases/news-details/2025/Itchy-and-Sneezy-More-Pets-are-Seeking-Allergy-Relief-2025-yG3z-9yJvj/default.aspx (allergy claims up 7% nationally over 5 years and 34% in Texas; cocker spaniels, English bulldogs and Westies had the most allergy claims)
  4. Burns K. More itchy pets? No problem. JAVMA News. February 15, 2020. https://www.avma.org/javma-news/2020-02-15/more-itchy-pets-no-problem
  5. Hillier A, Griffin CE. The ACVD task force on canine atopic dermatitis (I): incidence and prevalence. Vet Immunol Immunopathol. 2001;81(3-4):147-151.
  6. Frick OL, Brooks DL. Immunoglobulin E antibodies to pollens augmented in dogs by virus vaccines. Am J Vet Res. 1983;44(3):440-445. PMID 6301317. (inbred atopic dog colony; IgE measured by passive cutaneous anaphylaxis)
  7. Jaeger K, Linek M, Power HT, Bettenay SV, Zabel S, Rosychuk RAW, Mueller RS. Breed and site predispositions of dogs with atopic dermatitis: a comparison of five locations in three continents. Vet Dermatol. 2010;21(1):119-123.
  8. Merck Veterinary Manual (professional version). Atopic dermatitis in dogs. https://www.merckvetmanual.com/integumentary-system/atopic-dermatitis/atopic-dermatitis-in-dogs (accessed 2026-10-06)
  9. Hakanen E, Lehtimäki J, Salmela E, et al. Urban environment predisposes dogs and their owners to allergic symptoms. Sci Rep. 2018;8:1585. doi:10.1038/s41598-018-19953-3. PMID 29371634. PMCID PMC5785484.
  10. Anturaniemi J, Uusitalo L, Hielm-Björkman A. Environmental and phenotype-related risk factors for owner-reported allergic/atopic skin symptoms and for canine atopic dermatitis verified by veterinarian in a Finnish dog population. PLoS ONE. 2017;12(6):e0178771. PMCID PMC5453595.
  11. Lehtimäki J, Sinkko H, Hielm-Björkman A, et al. Skin microbiota and allergic symptoms associate with exposure to environmental microbes. Proc Natl Acad Sci USA. 2018;115(19):4897-4902. doi:10.1073/pnas.1719785115
  12. Meury S, Molitor V, Doherr MG, et al. Role of the environment in the development of canine atopic dermatitis in Labrador and golden retrievers. Vet Dermatol. 2011;22(4):327-334. (rural living, other animals and forest walks protective; regular bathing linked to higher risk)
  13. Harvey ND, Shaw SC, Craigon PJ, Blott SC, England GCW. Environmental risk factors for canine atopic dermatitis: a retrospective large-scale study in Labrador and golden retrievers. Vet Dermatol. 2019;30(5):396-e119. doi:10.1111/vde.12782. PMID 31407839. (2,445 dogs: 793 cases, 1,652 controls)
  14. Hemida M, Vuori KA, Salin S, Moore R, Anturaniemi J, Hielm-Björkman A. Identification of modifiable pre- and postnatal dietary and environmental exposures associated with owner-reported canine atopic dermatitis in Finland using a web-based questionnaire. PLoS ONE. 2020;15(5):e0225675. PMCID PMC7259748.
  15. Favrot C, Steffan J, Seewald W, Picco F. A prospective study on the clinical features of chronic canine atopic dermatitis and its diagnosis. Vet Dermatol. 2010;21(1):23-31. ("mostly indoor" as one of the criteria; 5 of 8 criteria: sensitivity 85%, specificity 79%)
  16. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5. PMID 26260508.
  17. Anderegg WRL, Abatzoglou JT, Anderegg LDL, Bielory L, Kinney PL, Ziska L. Anthropogenic climate change is worsening North American pollen seasons. Proc Natl Acad Sci USA. 2021;118(7):e2013284118. doi:10.1073/pnas.2013284118 (seasons start about 20 days earlier with about 21% more pollen, 1990 to 2018)
  18. Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Vet Res. 2016;12:9. doi:10.1186/s12917-016-0633-8. PMCID PMC4710035. (297 dogs; pooled provocation-confirmed cases from studies published 1985 to 2015)
  19. Detection of chicken DNA in commercial dog foods. BMC Vet Res. 2022 (published March 9, 2022). https://pmc.ncbi.nlm.nih.gov/articles/PMC8905904/ (11 of 15 foods matched their label; two had about 2% and almost 6% undeclared chicken DNA)
  20. Olivry T, Pucheu-Haston CM, Mayer U, Bergvall K, Bexley J. Identification of major and minor chicken allergens in dogs. Vet Dermatol. 2022;33(1):46-e16. doi:10.1111/vde.13029
  21. Hemida MBM, Salin S, Vuori KA, Moore R, Anturaniemi J, Rosendahl S, Barrouin-Melo SM, Hielm-Björkman A. Puppyhood diet as a factor in the development of owner-reported allergy/atopy skin signs in adult dogs in Finland. J Vet Intern Med. 2021;35(5):2374-2383. PMID 34258795. PMCID PMC8478020.
  22. McKenzie B, Larsen J. Letter regarding "Puppyhood diet as a factor in the development of owner-reported allergy/atopy skin signs in adult dogs in Finland." J Vet Intern Med. 2022;36(5). PMCID PMC9511089.
  23. Hemida M, et al. Response to letter regarding "Puppyhood diet as a factor in the development of owner-reported allergy/atopy skin signs in adult dogs in Finland." J Vet Intern Med. 2022;36(5). PMCID PMC9511083.
  24. Roine J, Uusitalo L, Hielm-Björkman A. Validating and reliability testing the descriptive data and three different disease diagnoses of the internet-based DOGRISK questionnaire. BMC Vet Res. 2016;12:30. doi:10.1186/s12917-016-0658-z. PMCID PMC4761135.
  25. van Rooijen C, Bosch G, van der Poel AFB, Wierenga PA, Alexander L, Hendriks WH. Quantitation of Maillard reaction products in commercially available pet foods. J Agric Food Chem. 2014;62(35):8883-8891. PMID 25088431. (67 foods; canned foods highest)
  26. Teodorowicz M, Hendriks WH, Wichers HJ, Savelkoul HFJ. Immunomodulation by processed animal feed: the role of Maillard reaction products and advanced glycation end-products (AGEs). Front Immunol. 2018;9:2088. doi:10.3389/fimmu.2018.02088
  27. Olivry T, Bizikova P. A systematic review of the evidence of reduced allergenicity and clinical benefit of food hydrolysates in dogs with cutaneous adverse food reactions. Vet Dermatol. 2010;21(1):32-41. (up to 50% of dogs worsened on partial hydrolysates of foods they were allergic to, in three controlled studies)
  28. van Bree FPJ, Bokken GCAM, Mineur R, et al. Zoonotic bacteria and parasites found in raw meat-based diets for cats and dogs. Vet Rec. 2018;182(2):50. (35 Dutch commercial frozen raw diets: Listeria monocytogenes 54%, ESBL-producing E. coli 80%, Salmonella 20%)
  29. Squires RA, Crawford C, Marcondes M, Whitley N. 2024 guidelines for the vaccination of dogs and cats, compiled by the Vaccination Guidelines Group (VGG) of the World Small Animal Veterinary Association (WSAVA). J Small Anim Pract. 2024;65(5):277-316. Available at wsava.org. (core vaccines; last puppy dose at 16 weeks or later; adult modified-live core boosters no more often than every 3 years; serology testing)
  30. Ellis J, Marziani E, et al. 2022 AAHA Canine Vaccination Guidelines. J Am Anim Hosp Assoc. 2022;58:213-230. doi:10.5326/JAAHA-MS-Canine-Vaccination-Guidelines (rabies as core; lifestyle-based non-core vaccines; leptospirosis recommended for most dogs; fewer vaccines per visit to reduce adverse-event risk)
  31. Texas Administrative Code, Title 25, §169.29 (rabies vaccination requirements for dogs and cats). https://www.law.cornell.edu/regulations/texas/25-Tex-Admin-Code-SS-169-29 (vaccination by 16 weeks with a USDA-licensed vaccine; boosters on the vaccine's labeled duration of immunity)
  32. Moore GE, Guptill LF, Ward MP, Glickman NW, Faunt KK, Lewis HB, Glickman LT. Adverse events diagnosed within three days of vaccine administration in dogs. J Am Vet Med Assoc. 2005;227(7):1102-1108. PMID 16220670. (1,226,159 dogs; 38.2 events per 10,000 dogs; risk up 27% per additional vaccine in dogs 10 kg or less)
  33. Moore GE, Morrison J, Saito EK, Spofford N, Yang M. Breed, smaller weight, and multiple injections are associated with increased adverse event reports within three days following canine vaccine administration. J Am Vet Med Assoc. 2023. doi:10.2460/javma.23.03.0181 (4,654,187 dogs at 1,119 Banfield hospitals)
  34. Ohmori K, Masuda K, Maeda S, et al. IgE reactivity to vaccine components in dogs that developed immediate-type allergic reactions after vaccination. Vet Immunol Immunopathol. 2005;104(3-4):249-256.
  35. Gershwin LJ. Adverse reactions to vaccination: from anaphylaxis to autoimmunity. Vet Clin North Am Small Anim Pract. 2018;48(2):279-290.
  36. Nødtvedt A, Bergvall K, Sallander M, Egenvall A, Emanuelson U, Hedhammar Å. A case-control study of risk factors for canine atopic dermatitis among boxer, bullterrier and West Highland white terrier dogs in Sweden. Vet Dermatol. 2007;18(5):309-315. (119 dogs; no effect of vaccination on the odds of developing atopic dermatitis)
  37. Navaratna S, Estcourt MJ, Burgess J, et al. Childhood vaccination and allergy: a systematic review and meta-analysis. Allergy. 2021.
  38. Institute of Medicine. The Childhood Immunization Schedule and Safety: Stakeholder Concerns, Scientific Evidence, and Future Studies. Washington, DC: National Academies Press; 2013. doi:10.17226/13563
  39. Schultz RD, Thiel B, Mukhtar E, Sharp P, Larson LJ. Age and long-term protective immunity in dogs and cats. J Comp Pathol. 2010;142(Suppl 1):S102-S108. (minimum duration of immunity of 7 years or more for distemper, adenovirus and parvovirus after modified-live vaccines)
  40. European Medicines Agency. Cytopoint (lokivetmab): EPAR and Summary of Product Characteristics (no interactions seen with vaccines in field studies; give vaccines at a different site). https://www.ema.europa.eu/en/documents/overview/cytopoint-epar-medicine-overview_en.pdf. UK Veterinary Medicines Directorate product information: https://www.vmd.defra.gov.uk/productinformationdatabase/files/QRD_Documents/QRD-Auth_2169259.PDF

Chapter 6: Fleas first, even if you've never seen one

  1. Merck Veterinary Manual, professional version. Flea Allergy Dermatitis in Dogs and Cats. https://www.merckvetmanual.com/integumentary-system/fleas-and-flea-allergy-dermatitis/flea-allergy-dermatitis-in-dogs-and-cats (flea allergy is the most common skin disease of dogs in the southern US; diagnosis by history, signs and response to flea control)
  2. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5 (rule out flea allergy with flea control before diagnosing atopy)
  3. WHO/IUIS Allergen Nomenclature Sub-Committee. Allergen database entry: Cte f 1 (Ctenocephalides felis salivary allergen). https://www.allergen.org/viewallergen.php?aid=247
  4. University of Arizona Cooperative Extension. Fleas (fact sheet). https://extension.arizona.edu/sites/extension.arizona.edu/files/attachment/Fleas.pdf ; see also https://cales.arizona.edu/yavapai/anr/hort/byg/archive/managingfleas2018.html (about 50% eggs, 35% larvae, 10% pupae, 5% adults)
  5. Rust MK, Dryden MW. The biology, ecology, and management of the cat flea. Annu Rev Entomol. 1997;42:451-473. (cat flea as the main flea of dogs and cats; life cycle; pupae protected in the cocoon and emergence triggered by host cues)
  6. Merck Veterinary Manual, professional version. Fleas in Dogs and Cats. https://www.merckvetmanual.com/integumentary-system/fleas-and-flea-allergy-dermatitis/fleas-in-dogs-and-cats (egg-laying begins within 24 to 48 hours of the first blood meal; up to 40 to 50 eggs a day at peak)
  7. Texas A&M University College of Veterinary Medicine & Biomedical Sciences. Prevention of Fleas is Important Year-Round. Pet Talk. https://vetmed.tamu.edu/news/pet-talk/prevention-of-fleas-important-year-round/
  8. Companion Animal Parasite Council. CAPC Guidelines: Fleas. https://capcvet.org/guidelines/fleas/ (year-round treatment of all dogs; fleas can complete the life cycle indoors; every pet in the home must be treated; established infestations can take several months to control)
  9. Blagburn BL, Dryden MW. Biology, treatment, and control of flea and tick infestations. Vet Clin North Am Small Anim Pract. 2009;39(6):1173-1200.
  10. Dryden MW, Smith V, Chwala M, et al. Evaluation of afoxolaner chewables to control flea populations in naturally infested dogs in private residences in Tampa FL, USA. Parasit Vectors. 2015;8:286. doi:10.1186/s13071-015-0897-z (37 dogs in 23 homes; 99.3% reduction in on-dog flea counts by day 7; 36 of 37 dogs flea-free at one month; industry-funded)
  11. Dryden MW, Canfield MS, Kalosy K, et al. Evaluation of fluralaner and afoxolaner treatments to control flea populations, reduce pruritus and minimize dermatologic lesions in naturally infested dogs in private residences in west central Florida USA. Parasit Vectors. 2016;9:365. doi:10.1186/s13071-016-1654-7. PMCID PMC4924230. (industry-funded)
  12. Boland LA, Angles JM. Feline permethrin toxicity: retrospective study of 42 cases. J Feline Med Surg. 2010;12(2):61-71. PMID 20123482. (mostly canine spot-ons applied to cats; tremors in 86%, seizures in 33%)
  13. US Food and Drug Administration, Center for Veterinary Medicine. Animal Drug Safety Communication: FDA Alerts Pet Owners and Veterinarians About Potential for Neurologic Adverse Events Associated with Certain Flea and Tick Products. CVM Update, September 20, 2018. https://www.fda.gov/animal-veterinary/cvm-updates/animal-drug-safety-communication-fda-alerts-pet-owners-and-veterinarians-about-potential-neurologic ; see also JAVMA News, Four flea, tick products linked to seizures, ataxia, November 15, 2018.
  14. US Food and Drug Administration. Fact Sheet for Pet Owners and Veterinarians about Potential Adverse Events Associated with Isoxazoline Flea and Tick Products. https://www.fda.gov/animal-veterinary/animal-health-literacy/fact-sheet-pet-owners-and-veterinarians-about-potential-adverse-events-associated-isoxazoline-flea (most animals have not had reactions; the products remain safe and effective for the majority of animals)
  15. Boehringer Ingelheim Animal Health. NexGard (afoxolaner) Chewables for Dogs, US package insert, Precautions section. https://vetlabel.com/lib/vet/meds/nexgard/ (use with caution in dogs with a history of seizures or neurologic disorders)
  16. European Medicines Agency. Summaries of product characteristics for isoxazoline products (for example, NexGard and Bravecto), section 4.6, adverse reactions. (neurological signs listed as "very rare," meaning fewer than 1 in 10,000 animals treated)
  17. Bates N, Dijkman MA, Edwards JN. Neurological adverse effects of isoxazoline exposure in cats and dogs. Vet Rec. 2024;194(12):e4149. doi:10.1002/vetr.4149 (79 cases over 9 years from UK and Dutch poison centers; all animals with known outcome recovered)
  18. US Food and Drug Administration. Freedom of Information summary, IMOXI (imidacloprid + moxidectin) Topical Solution for Dogs, ANADA 200-615, Vetoquinol USA, approved December 19, 2019. https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/8067 (generic of Advantage Multi for Dogs; heartworm prevention and flea control)
  19. Zoetis. Revolution (selamectin) Topical Solution, US package insert.
  20. US Food and Drug Administration, Center for Veterinary Medicine. FDA Approves ProHeart 12 (moxidectin) for Prevention of Heartworm Disease in Dogs. CVM Update, July 2, 2019. https://www.fda.gov/animal-veterinary/cvm-updates/fda-approves-proheart-12-moxidectin-prevention-heartworm-disease-dogs ; JAVMA News. ProHeart 6 returns to U.S. market on limited basis. 2008. (ProHeart 6 withdrawn at FDA's request in 2004, returned in 2008 under a risk minimization program)
  21. Merck Veterinary Manual, professional version. Isoxazoline Toxicosis in Animals. https://www.merckvetmanual.com/toxicology/insecticide-and-acaricide-organic-toxicity/isoxazoline-toxicosis-in-animals (greater selectivity for insect and mite nerve receptors than for mammalian ones)
  22. Beugnet F, de Vos C, Liebenberg J, Halos L, Larsen D, Fourie J. Efficacy of afoxolaner in a clinical field study in dogs naturally infested with Sarcoptes scabiei. Parasite. 2016;23:26.
  23. Knowledge summary comparing isoxazolines with imidacloprid/moxidectin for canine generalized demodicosis. Veterinary Evidence. 2019;4(2). https://veterinaryevidence.org/index.php/ve/article/view/183 (five randomized trials; isoxazolines at least as effective)
  24. University of Minnesota Libraries. Animal Dermatology (open textbook), chapter Canine Sarcoptic Mange. https://open.lib.umn.edu/animaldermatology/chapter/canine-sarcoptic-mange (pinnal-pedal reflex in about 50 to 90% of dogs; skin scrapings find mites in only 25 to 50%)
  25. Cornell University College of Veterinary Medicine, Riney Canine Health Center. Sarcoptic mange (scabies). https://www.vet.cornell.edu/departments/riney-canine-health-center/canine-health-information/sarcoptic-mange-scabies (contagious to people; short-lived in healthy people once household dogs are treated)
  26. Mueller RS, Rosenkrantz W, Bensignor E, Karaś-Tęcza J, Paterson T, Shipstone MA. Diagnosis and treatment of demodicosis in dogs and cats: clinical consensus guidelines of the World Association for Veterinary Dermatology. Vet Dermatol. 2020;31(1):5-27.
  27. Western College of Veterinary Medicine, University of Saskatchewan. Cheyletiella species. Learn About Parasites. https://wcvm.usask.ca/learnaboutparasites/parasites/cheyletiella-species.php (can cause temporary infestation in people)
  28. Companion Animal Parasite Council. CAPC Guidelines: Lice. https://capcvet.org/guidelines/lice/
  29. Genovese AG, McLean MK, Khan SA. Adverse reactions from essential oil-containing natural flea products exempted from Environmental Protection Agency regulations in dogs and cats. J Vet Emerg Crit Care. 2012;22(4):470-475. PMID 22805458. (ASPCA Animal Poison Control Center records, 2006 to 2008)
  30. Author's clinic pricing, Cypress, Texas, 2026; Hearthstone Animal Clinic, dog allergies page, Cypress, Texas. Estimates only; prices vary by clinic, city and dog size.

Chapter 7: The infection layer: staph, yeast and stinky ears

  1. Santoro D, Marsella R, Pucheu-Haston CM, et al. Review: Pathogenesis of canine atopic dermatitis: skin barrier and host-micro-organism interaction. Vet Dermatol. 2015;26(2):84-e25.
  2. Loeffler A, Cain CL, Ferrer L, Nishifuji K, et al. Antimicrobial use guidelines for canine pyoderma by the International Society for Companion Animal Infectious Diseases (ISCAID). Vet Dermatol. 2025;36(3):234-282. doi:10.1111/vde.13342. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12058580/ (cytology before antimicrobials; topical therapy, with 2 to 4% chlorhexidine best studied; systemic therapy initially 2 weeks for superficial and 3 weeks for deep pyoderma, then re-examination)
  3. Bond R, Morris DO, Guillot J, Bensignor EJ, Robson D, Mason KV, Kano R, Hill PB. Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology. Vet Dermatol. 2020;31(1):28-74. doi:10.1111/vde.12809. PMCID PMC7059102.
  4. Olivry T, DeBoer DJ, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6
  5. Hillier A, Lloyd DH, Weese JS, et al. Guidelines for the diagnosis and antimicrobial therapy of canine superficial bacterial folliculitis (Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases). Vet Dermatol. 2014;25(3):163-175, e42-e43.
  6. Koch S. Treating canine superficial pyoderma in the era of antimicrobial resistance. Today's Veterinary Practice. https://todaysveterinarypractice.com/dermatology/treating-canine-superficial-pyoderma-in-the-era-of-antimicrobial-resistance/ (papules, short-lived pustules, crusts and epidermal collarettes)
  7. Morris DO, Olivier NB, Rosser EJ. Type-1 hypersensitivity reactions to Malassezia pachydermatis extracts in atopic dogs. Am J Vet Res. 1998;59(7):836-841.
  8. Saridomichelakis MN, Farmaki R, Leontides LS, Koutinas AF. Aetiology of canine otitis externa: a retrospective study of 100 cases. Vet Dermatol. 2007;18(5):341-347. (allergic skin disease the primary cause in 43 of 100 dogs; 93% affected both ears)
  9. Neptra (florfenicol, terbinafine hydrochloride, mometasone furoate) otic solution, product labeling. EU summary of product characteristics: https://www.ema.europa.eu/es/documents/product-information/neptra-epar-product-information_es.pdf ; Elanco product detailer: https://assets.elanco.com/0cec44ed-3eaa-0009-2029-666567e7e4de/da6e4fd0-6ece-4ab5-957b-25d398014370/Neptra%20Mini%20Detailer%202024.pdf (eardrum must be confirmed intact before use; single treatment)
  10. Virbac. Easotic (hydrocortisone aceponate, miconazole nitrate, gentamicin sulfate) otic suspension, US package insert, April 2024. https://vetlabel.com/lib/vet/meds/easotic/ ; https://vet-us.virbac.com/files/live/sites/virbac-b2b-usa/files/client-leaflet/2024%20PIs/Ear%20Health/EASOTIC%2004-2024%20302076-06%20PI.pdf (once daily for 5 days; not for use with a known perforated eardrum)
  11. Merck Animal Health. Mometamax Single otic, product label. https://www.merck-animal-health-usa.com/offload-downloads/mometamax-single-product-label (single in-clinic dose of gentamicin, posaconazole and mometasone)
  12. Elanco. Claro (florfenicol, terbinafine, mometasone furoate) otic solution, product information. https://vetlabel.com/lib/vet/meds/claro/ ; https://my.elanco.com/us/claro-neptra (single veterinarian-administered dose; up to 30 days' duration)
  13. Osurnia (florfenicol, terbinafine, betamethasone acetate) otic gel, package insert and FDA Freedom of Information summary. https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/928 ; https://image.chewy.com/is/content/catalog/146159_PackageInsert._V1561063617_.pdf (one tube per affected ear, repeated in 7 days)
  14. Clinician's Brief. Pseudomonas otitis infection in cats and dogs. https://www.cliniciansbrief.com/article/pseudomonas-otitis-infection-cats-and-dogs (Pseudomonas aeruginosa is naturally resistant to many drugs; chronic and end-stage ears)
  15. IDEXX. Mucky ears, swabs and smears: a guide to interpreting diagnostics for otitis externa (BSAVA 2025). https://idexx.co.uk/files/mucky-ears-swabs-and-smears-a-guide-to-interpreting-diagnostics-for-otitis-externa-bsava-2025.pdf (rods on ear cytology raise concern for Pseudomonas and call for a culture; industry-produced)
  16. Loeffler A, Lloyd DH. What has changed in canine pyoderma? A narrative review. Vet J. 2018;235:24-32. doi:10.1016/j.tvjl.2018.04.002
  17. Lord J, Millis N, Jones RD, Johnson B, Kania SA, Odoi A. Patterns of antimicrobial, multidrug and methicillin resistance among Staphylococcus spp. isolated from canine specimens submitted to a diagnostic laboratory in Tennessee, USA: a descriptive study. BMC Vet Res. 2022;18:91. doi:10.1186/s12917-022-03185-9. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8903740/ (30.8% of 6,453 S. pseudintermedius isolates methicillin-resistant, 2006 to 2017, rising over time)
  18. Lehner G, Linek M, Bond R, Lloyd DH, Prenger-Berninghoff E, Thom N, Straube I, Verheyen K, Loeffler A. Case-control risk factor study of methicillin-resistant Staphylococcus pseudintermedius (MRSP) infection in dogs and cats in Germany. Vet Microbiol. 2014;168(1):154-160. doi:10.1016/j.vetmic.2013.10.023
  19. Borio S, Colombo S, La Rosa G, De Lucia M, Damborg P, Guardabassi L. Effectiveness of a combined (4% chlorhexidine digluconate shampoo and solution) protocol in MRS and non-MRS canine superficial pyoderma: a randomized, blinded, antibiotic-controlled study. Vet Dermatol. 2015;26(5):339-344, e72.
  20. Negre A, Bensignor E, Guillot J. Evidence-based veterinary dermatology: a systematic review of interventions for Malassezia dermatitis in dogs. Vet Dermatol. 2009;20(1):1-12.
  21. Zoetis. CYTOPOINT (lokivetmab) US package insert, immunogenicity section. https://www.drugs.com/vet/cytopoint.html ; European Medicines Agency. Cytopoint EPAR medicine overview. https://www.ema.europa.eu/en/documents/overview/cytopoint-epar-medicine-overview_en.pdf (antibodies against the drug are uncommon)
  22. Zoetis. APOQUEL (oclacitinib tablet) US prescribing information. https://vetlabel.com/lib/vet/meds/apoquel/
  23. Virginia-Maryland College of Veterinary Medicine. Canine hot spots. July 2025. https://news.vt.edu/articles/2025/07/vetmed-pet-canine-hot-spots.html (pyotraumatic dermatitis; rapid onset; common underlying causes)
  24. Holm BR, Rest JR, Seewald W. A prospective study of the clinical findings, treatment and histopathology of 44 cases of pyotraumatic dermatitis. Vet Dermatol. 2004;15(6):369-376.
  25. Shumaker AK, Angus JC, Coyner KS, Loeffler DG, Rankin SC, Lewis TP. Microbiological and histopathological features of canine acral lick dermatitis. Vet Dermatol. 2008;19(5):288-298. (deep infection in 29 of 31 lesions; only 8 of 22 surface cultures matched the deep culture)
  26. Today's Veterinary Practice. Topical therapy for otitis externa. https://todaysveterinarypractice.com/dermatology/topical-therapy-for-otitis-externa/ (cleaning too often can keep an ear inflamed)
  27. Guillot J, Bond R. Malassezia yeasts in veterinary dermatology: an updated overview. Front Cell Infect Microbiol. 2020;10:79. doi:10.3389/fcimb.2020.00079 (Malassezia are fat-loving yeasts that live normally on the skin and overgrow when given the chance)
  28. Author's clinic pricing, Cypress, Texas, 2026; Hearthstone Animal Clinic, dog allergies page, Cypress, Texas. Estimates only; prices vary by clinic, city and dog size.

Chapter 8: Food allergy

  1. Olivry T, Mueller RS, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (1): duration of elimination diets. BMC Vet Res. 2015;11:225. doi:10.1186/s12917-015-0541-3. PMCID PMC4551374. (source of the terms adverse food reaction, food allergy and food intolerance used in this chapter)
  2. Mueller RS, Olivry T. Critically appraised topic on adverse food reactions of companion animals (4): can we diagnose adverse food reactions in dogs and cats with in vivo or in vitro tests? BMC Vet Res. 2017;13:275. doi:10.1186/s12917-017-1142-0. PMCID PMC5577833.
  3. Gaschen FP, Merchant SR. Adverse food reactions in dogs and cats. Vet Clin North Am Small Anim Pract. 2011;41(2):361-379. (review of oral tolerance and food allergy mechanisms; much of the underlying immunology comes from human and rodent research)
  4. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (3): prevalence of cutaneous adverse food reactions in dogs and cats. BMC Vet Res. 2017;13:51. doi:10.1186/s12917-017-0973-z. PMCID PMC5311844.
  5. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (9): time to flare of cutaneous signs after a dietary challenge in dogs and cats with food allergies. BMC Vet Res. 2020;16:158. doi:10.1186/s12917-020-02379-3. PMCID PMC7247231. (234 dogs; about 9% flared on day 1, about 21% by day 2, more than 90% within 14 days)
  6. Bethlehem S, Bexley J, Mueller RS. Patch testing and allergen-specific serum IgE and IgG antibodies in the diagnosis of canine adverse food reactions. Vet Immunol Immunopathol. 2012;145(3-4):582-589. PMID 22301200. (serum IgE sensitivity 6.7%, IgG 26.7%)
  7. Olivry T, Pucheu-Haston CM, Mayer U, Bergvall K, Bexley J. Identification of major and minor chicken allergens in dogs. Vet Dermatol. 2022;33(1):46-e16. doi:10.1111/vde.13029. (seven major allergens and one minor; six of the eight are known to cross-react between chicken and fish)
  8. Martín Á, Sierra MP, González JL, Arévalo MÁ. Identification of allergens responsible for canine cutaneous adverse food reactions to lamb, beef and cow's milk. Vet Dermatol. 2004;15(6):349-356. doi:10.1111/j.1365-3164.2004.00404.x
  9. Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Vet Res. 2016;12:9. doi:10.1186/s12917-016-0633-8. PMCID PMC4710035. (pooled provocation-confirmed cases from studies published 1985 to 2015; 297 dogs: beef 102, dairy 51, chicken 45, wheat 38, soy 18, lamb 14)
  10. Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Vet Res. 2016;12:9. doi:10.1186/s12917-016-0633-8. PMCID PMC4710035. (smaller figures from the same 297 dogs: soy 18, corn 13, egg 11, pork 7, fish 5, rice 5)
  11. Cross-reactivity among poultry species (chicken, turkey, duck) is inferred from the high similarity of the chicken allergens across bird species. See Olivry T, Pucheu-Haston CM, Mayer U, Bergvall K, Bexley J. Identification of major and minor chicken allergens in dogs. Vet Dermatol. 2022;33(1):46-e16. doi:10.1111/vde.13029.
  12. Bexley J, Kingswell N, Olivry T. Serum IgE cross-reactivity between fish and chicken meats in dogs. Vet Dermatol. 2019;30(1):25-e8.
  13. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5 (food-induced and environmental atopic dermatitis can look the same)
  14. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (7): signalment and cutaneous manifestations of dogs and cats with adverse food reactions. BMC Vet Res. 2019;15:140. doi:10.1186/s12917-019-1880-2. PMCID PMC6507158. (825 dogs; ears, feet and belly often affected; ear disease can be the only sign)
  15. Onset before about 1 year or after about 6 to 7 years of age is a common clinical teaching pattern, not a figure from a single study. For age at onset in food-allergic dogs, see Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (7). BMC Vet Res. 2019;15:140. doi:10.1186/s12917-019-1880-2.
  16. Mueller RS, Olivry T. Critically appraised topic on adverse food reactions of companion animals (6): prevalence of noncutaneous manifestations of adverse food reactions in dogs and cats. BMC Vet Res. 2018;14:341. doi:10.1186/s12917-018-1656-0. PMCID PMC6233561. (vomiting or diarrhea in more than 20% of dogs with adverse food reactions)
  17. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (3): prevalence of cutaneous adverse food reactions in dogs and cats. BMC Vet Res. 2017;13:51. doi:10.1186/s12917-017-0973-z. PMCID PMC5311844. (1 to 2% of all dogs seen by vets; 9 to 40% of itchy dogs; 9 to 50% of dogs with atopic dermatitis)
  18. US Food and Drug Administration, Center for Veterinary Medicine. FDA investigation into potential link between certain diets and canine dilated cardiomyopathy (investigation page and updates, 2018 to 2022). https://www.fda.gov/animal-veterinary/outbreaks-and-advisories/fda-investigation-potential-link-between-certain-diets-and-canine-dilated-cardiomyopathy
  19. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (5): discrepancies between ingredients and labeling in commercial pet foods. BMC Vet Res. 2018;14:24. doi:10.1186/s12917-018-1346-y. PMID 29357847. PMCID PMC5778722. (mislabeling "rather common," including in novel and limited-ingredient foods; hydrolyzed diets performed best)
  20. See Chapter 10, references on consumer allergy test kits and their prices.

Chapter 9: The food trial, done right

  1. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (3): prevalence of cutaneous adverse food reactions in dogs and cats. BMC Vet Res. 2017;13:51. doi:10.1186/s12917-017-0973-z (food allergy in 9 to 40% of itchy dogs; often found alongside atopic dermatitis)
  2. Mueller RS, Olivry T. Critically appraised topic on adverse food reactions of companion animals (4): can we diagnose adverse food reactions in dogs and cats with in vivo or in vitro tests? BMC Vet Res. 2017;13:275. doi:10.1186/s12917-017-1142-0
  3. Manufacturer product information: Royal Canin Veterinary Diet Vegetarian; Rayne Clinical Nutrition vegetarian and novel-protein (venison, rabbit, alligator) diets.
  4. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (5): discrepancies between ingredients and labeling in commercial pet foods. BMC Vet Res. 2018;14:24. doi:10.1186/s12917-018-1346-y. PMID 29357847 (mislabeling "rather common"; hydrolyzed diets performed best)
  5. Manufacturer product information: Hill's Prescription Diet z/d (hydrolyzed chicken liver); Purina Pro Plan Veterinary Diets HA Hydrolyzed (soy-based; chicken-flavored and vegetarian versions exist); Royal Canin Veterinary Diet Hydrolyzed Protein HP (hydrolyzed soy); Royal Canin Ultamino (extensively hydrolyzed poultry feather).
  6. Martín Á, Sierra MP, González JL, Arévalo MÁ. Identification of allergens responsible for canine cutaneous adverse food reactions to lamb, beef and cow's milk. Vet Dermatol. 2004;15(6):349-356. doi:10.1111/j.1365-3164.2004.00404.x
  7. Bexley J, Kingswell N, Olivry T. Serum IgE cross-reactivity between fish and chicken meats in dogs. Vet Dermatol. 2019;30(1):25-e8.
  8. Olivry T, Pucheu-Haston CM, Mayer U, Bergvall K, Bexley J. Identification of major and minor chicken allergens in dogs. Vet Dermatol. 2022;33(1):46-e16. doi:10.1111/vde.13029
  9. Home-cooked elimination diets are labor-intensive and are not balanced for long-term feeding without a recipe from a board-certified veterinary nutritionist. See AAHA 2023 Management of Allergic Skin Diseases in Dogs and Cats Guidelines (ref. 18) and Gaschen FP, Merchant SR. Adverse food reactions in dogs and cats. Vet Clin North Am Small Anim Pract. 2011;41(2):361-379 (ref. 28).
  10. Raditic DM, Remillard RL, Tater KC. ELISA testing for common food antigens in four dry dog foods used in dietary elimination trials. J Anim Physiol Anim Nutr (Berl). 2011;95(1):90-97.
  11. Ricci R, Granato A, Vascellari M, et al. Identification of undeclared sources of animal origin in canine dry foods used in dietary elimination trials. J Anim Physiol Anim Nutr (Berl). 2013;97(Suppl 1):32-38. (12 diets; only 2 matched their labels on both microscopy and PCR)
  12. Willis-Mahn C, Remillard R, Tater K. ELISA testing for soy antigens in dry dog foods used in dietary elimination trials. J Am Anim Hosp Assoc. 2014;50(6):383-389. (3 of 4 over-the-counter "no soy" diets contained soy; 4 of 7 veterinary therapeutic diets had detectable soy)
  13. Horvath-Ungerboeck C, Widmann K, Handl S. Detection of DNA from undeclared animal species in commercial elimination diets for dogs using PCR. Vet Dermatol. 2017;28(4):373-e86. doi:10.1111/vde.12431. PMID 28247445
  14. Pagani E, Ricci R, Contiero B, et al. Cross-contamination in canine and feline dietetic limited-antigen wet diets. BMC Vet Res. 2018;14:283. doi:10.1186/s12917-018-1571-4. PMID 30208880. PMCID PMC6136174. (hydrolyzed and vegetarian diets tested clean)
  15. Fossati LA, Larsen JA, Villaverde C, Fascetti AJ. Determination of mammalian DNA in commercial canine diets with uncommon and limited ingredients. Vet Med Sci. 2019;5(1):30-38. https://doaj.org/article/7e508f0d09e04b6ea17eafdc6688255f (all 21 over-the-counter limited- or single-protein dry diets contained undeclared mammal DNA)
  16. Olivry T, Mueller RS, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (1): duration of elimination diets. BMC Vet Res. 2015;11:225. doi:10.1186/s12917-015-0541-3
  17. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5 (elimination diet restrictions; treating infections and short-term itch medicine during the trial)
  18. American Animal Hospital Association. 2023 AAHA Management of Allergic Skin Diseases in Dogs and Cats Guidelines, and toolkit handout Busting Common Myths about Cutaneous Adverse Food Reactions. https://24051120.fs1.hubspotusercontent-na1.net/hubfs/24051120/Guidelines%20PDFs/Allergic%20Skin%20Diseases/Toolkit/AllergicDiseaseGL_BustingCommonMyths.pdf
  19. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (9): time to flare of cutaneous signs after a dietary challenge in dogs and cats with food allergies. BMC Vet Res. 2020;16:158. doi:10.1186/s12917-020-02379-3 (234 dogs; about 9% flared on day 1, 21% by day 2, more than 90% within 14 days)
  20. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (8): storage mites in commercial pet foods. BMC Vet Res. 2019;15:385. doi:10.1186/s12917-019-2102-7
  21. Hill PB, Lau P, Rybnicek J. Development of an owner-assessed scale to measure the severity of pruritus in dogs. Vet Dermatol. 2007;18(5):301-308.
  22. Rybnicek J, Lau-Gillard PJ, Harvey R, Hill PB. Further validation of a pruritus severity scale for use in dogs. Vet Dermatol. 2009;20(2):115-122. (713 owners, 408 dogs with skin disease; normal range 0 to 1.9)
  23. Mueller RS, Olivry T. Critically appraised topic on adverse food reactions of companion animals (6): prevalence of noncutaneous manifestations of adverse food reactions in dogs and cats. BMC Vet Res. 2018;14:341. doi:10.1186/s12917-018-1656-0 (vomiting or diarrhea in more than 20% of dogs with adverse food reactions)
  24. Jeffers JG, Meyer EK, Sosis EJ. Responses of dogs with food allergies to single-ingredient dietary provocation. J Am Vet Med Assoc. 1996;209(3):608-611. PMID 8755979. (64% reacted to two or more proteins; mean 2.4 allergens per dog)
  25. Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Vet Res. 2016;12:9. doi:10.1186/s12917-016-0633-8 (297 dogs from studies published 1985 to 2015; many reacted to more than one food)
  26. Olivry T, Bizikova P. A systematic review of the evidence of reduced allergenicity and clinical benefit of food hydrolysates in dogs with cutaneous adverse food reactions. Vet Dermatol. 2010;21(1):32-41. (up to 50% of dogs in three controlled studies flared on partial hydrolysates of foods they were allergic to)
  27. Bizikova P, Olivry T. A randomized, double-blinded crossover trial testing the benefit of two hydrolysed poultry-based commercial diets for dogs with spontaneous pruritic chicken allergy. Vet Dermatol. 2016;27(4):289-e70. doi:10.1111/vde.12302
  28. Gaschen FP, Merchant SR. Adverse food reactions in dogs and cats. Vet Clin North Am Small Anim Pract. 2011;41(2):361-379. (IgE-mediated and T-cell-mediated mechanisms)
  29. Olivry T, Mueller RS. Critically appraised topic on adverse food reactions of companion animals (7): signalment and cutaneous manifestations of dogs and cats with adverse food reactions. BMC Vet Res. 2019;15:140. doi:10.1186/s12917-019-1880-2. PMCID PMC6507158. (825 dogs; onset from under 1 year to 13 years)
  30. Author's clinic pricing, Cypress, Texas, 2026; Hearthstone Animal Clinic, dog allergies page, Cypress, Texas. (prescription diet about $100 to $250 a month for a Lab-sized dog; canned versions roughly 2 to 3 times the cost of dry) Estimates only; prices vary by clinic, retailer and dog size.

Chapter 10: Tests that lie (and the ones that don't)

  1. Coyner K, Schick A. Hair and saliva analysis fails to accurately identify atopic dogs or differentiate real and fake samples. Vet Dermatol. 2019;30(1). doi:10.1111/vde.12716. PMID 30680834. https://pubmed.ncbi.nlm.nih.gov/30680834/ (every sample tested positive, including synthetic fur and sterile saline; repeat samples agreed no better than chance)
  2. Lian TM, Halliwell REW. Allergen-specific IgE and IgGd antibodies in atopic and normal dogs. Vet Immunol Immunopathol. 1998;66(3-4):203-223. (healthy dogs' dust mite IgE did not differ significantly from atopic dogs')
  3. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5. PMID 26260508. (allergy tests pick allergens for immunotherapy, not diagnose atopy; false positives and negatives with both intradermal and blood tests)
  4. Mueller RS, Olivry T. Critically appraised topic on adverse food reactions of companion animals (4): can we diagnose adverse food reactions in dogs and cats with in vivo or in vitro tests? BMC Vet Res. 2017;13:275. doi:10.1186/s12917-017-1142-0. PMCID PMC5577833.
  5. Wüthrich B. Unproven techniques in allergy diagnosis. J Investig Allergol Clin Immunol. 2005;15(2):86-90. PMID 16047707. (human allergy medicine)
  6. Bethlehem S, Bexley J, Mueller RS. Patch testing and allergen-specific serum IgE and IgG antibodies in the diagnosis of canine adverse food reactions. Vet Immunol Immunopathol. 2012;145(3-4):582-589. PMID 22301200. https://pubmed.ncbi.nlm.nih.gov/22301200/ (serum IgE sensitivity 6.7%; serum IgG sensitivity 26.7%; patch test sensitivity 96.7%)
  7. Udraite Vovk L, Watson A, Dodds WJ, Klinger CJ, Classen J, Mueller RS. Testing for food-specific antibodies in saliva and blood of food allergic and healthy dogs. Vet J. 2019;245:1-6. doi:10.1016/j.tvjl.2018.12.014.
  8. Bexley J, Kingswell N, Olivry T. Serum IgE cross-reactivity between fish and chicken meats in dogs. Vet Dermatol. 2019;30(1):25-e8.
  9. Foster AP, Littlewood JD, Webb P, Wood JLN, Rogers K, Shaw SE. Comparison of intradermal and serum testing for allergen-specific IgE using a FcεRIα-based assay in atopic dogs in the UK. Vet Immunol Immunopathol. 2003;93(1-2):51-60.
  10. Kasper B, Boehm T, Wittenstein N, Mueller RS. Cross-reactive carbohydrate determinants in atopic and healthy dogs and their influence on allergy test specificity. Vet Rec. 2023. doi:10.1002/vetr.3308. (34 atopic and 10 healthy dogs; agreement between skin and blood testing improved after blocking these carbohydrate antibodies)
  11. Eisenschenk MC, Hensel P, Saridomichelakis MN, Tamamoto-Mochizuki C, Pucheu-Haston CM, Santoro D. Introduction to the ICADA 2023 canine atopic dermatitis pathogenesis review articles and updated definition. Vet Dermatol. 2024;35(1). PMID 38095285.
  12. Fennis EEM, van Damme CMM, Schlotter YM, et al. Efficacy of subcutaneous allergen immunotherapy in atopic dogs: a retrospective study of 664 cases. Vet Dermatol. 2022;33(4):321-e75. PMCID PMC9544551. (two referral clinics, 2008 to 2018; excellent 31.5%, good 28.5%, poor 40.1%, judged after at least 9 months)
  13. Johansen C, Mariani C, Mueller RS. Evaluation of canine adverse food reactions by patch testing with single proteins, single carbohydrates and commercial foods. Vet Dermatol. 2017;28(5):473-e109. doi:10.1111/vde.12455. (25 dogs with confirmed food reactions; useful for choosing an elimination-diet protein, not for diagnosis)
  14. Olivry T, Mueller RS, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (1): duration of elimination diets. BMC Vet Res. 2015;11:225. doi:10.1186/s12917-015-0541-3
  15. Author's clinic pricing, Cypress, Texas, 2026; Hearthstone Animal Clinic, dog allergies page, Cypress, Texas. (intradermal testing range includes the dermatology consult and sedation) Estimates only; prices vary by clinic and city.
  16. Retail listings for direct-to-consumer pet hair and saliva "allergy" and "intolerance" test kits, viewed October 2026 (about $70 to $90 for common kits; review sites quote $50 to $200).

Chapter 11: Putting it together: the itch ladder

  1. Olivry T, DeBoer DJ, Favrot C, Jackson HA, Mueller RS, Nuttall T, Prélaud P; International Committee on Allergic Diseases of Animals (ICADA). Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6 (separate plans for acute flares and chronic management, flare factors, and combination therapy)
  2. Miller J, Simpson A, Bloom P, Diesel A, Friedeck A, Paterson T, Wisecup M, Yu CM. 2023 AAHA Management of Allergic Skin Diseases in Dogs and Cats Guidelines. J Am Anim Hosp Assoc. 2023;59(6):255-284. Table 2, Acute flare and long-term management therapies in dogs: https://www.aaha.org/resources/2023-aaha-management-of-allergic-skin-diseases-in-dogs-and-cats-guidelines/table-2-acute-flare-and-long-term-management-therapies-in-dogs/ (individualized, multimodal plans; lifelong management often needed)
  3. US Food and Drug Administration. Fact Sheet for Pet Owners and Veterinarians about Potential Adverse Events Associated with Isoxazoline Flea and Tick Products. See also Chapter 6, references on flea control for every pet with species- and weight-appropriate products. (minimum age and weight for NexGard-type chews per the current product label)
  4. Loeffler A, et al. ISCAID antimicrobial use guidelines for canine pyoderma. Vet Dermatol. 2025;36(3):234-282; and Bond R, et al. Malassezia consensus guidelines. Vet Dermatol. 2020;31(1):28-74. See also Chapter 7 references. (cytology at every flare; antibiotics plus medicated baths)
  5. Olivry T, Mueller RS, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (1): duration of elimination diets. BMC Vet Res. 2015;11:225. doi:10.1186/s12917-015-0541-3. (the 10- to 12-week trial length is the author's clinical position, explained in Chapter 9)
  6. Novartis Animal Health / Elanco. ATOPICA (cyclosporine, modified) capsules for dogs, US package insert. NADA 141-218, approved August 15, 2003. https://www.drugs.com/pro/atopica.html (about 4 weeks to judge; tapering after control; stomach upset the most common side effect)
  7. Fennis EEM, van Damme CMM, Schlotter YM, et al. Efficacy of subcutaneous allergen immunotherapy in atopic dogs: a retrospective study of 664 cases. Vet Dermatol. 2022;33(4):321-e75. PMCID PMC9544551. (59.9% of dogs at least 50% improved after at least 9 months)
  8. Hill PB, Lau P, Rybnicek J. Development of an owner-assessed scale to measure the severity of pruritus in dogs. Vet Dermatol. 2007;18(5):301-308. And: Rybnicek J, Lau-Gillard PJ, Harvey R, Hill PB. Further validation of a pruritus severity scale for use in dogs. Vet Dermatol. 2009;20(2):115-122. (normal dogs score 0 to 1.9; the 0-to-3 comfortable zone is the author's clinical definition, not a published cutoff)
  9. Cosgrove SB, Cleaver DM, King VL, Gilmer AR, Daniels AE, Wren JA, Stegemann MR. Long-term compassionate use of oclacitinib in dogs with atopic and allergic skin disease: safety, efficacy and quality of life. Vet Dermatol. 2015;26(3):171-179, e35. (247 dogs; at day 90, 63.9% had at least a 50% drop in owner-scored itch; open-label, no comparison group)
  10. Author's clinical experience, Hearthstone Animal Clinic, Cypress, Texas. (seasonal timing of ear infections and itchy-dog waves, and how many allergic dogs reach the comfortable zone; observation, not published data)
  11. Bachtel JC, Snidow M, et al. Efficacy of combination oclacitinib and lokivetmab therapies after monotherapeutic failure in 44 dogs: a retrospective study. Vet Dermatol. Published online 2025. doi:10.1111/vde.70034. PMID 41189387. (27 of 44 dogs that failed each drug alone responded to the combination; no adverse effects noted)
  12. Zoetis. APOQUEL (oclacitinib tablet) US prescribing information. https://vetlabel.com/lib/vet/meds/apoquel/ (not for dogs under 12 months or with serious infections; safety with steroids or cyclosporine not established). Zoetis press release, June 13, 2023: Apoquel Chewable approved June 9, 2023. Cost: Vetster, 2026.
  13. Veterinary Practice. Canine lichenification. https://veterinary-practice.com/article/canine-lichenification (good control may take many months; with an underlying cause such as atopy, control is lifelong)
  14. MSD / Merck Veterinary Manual. Acanthosis nigricans and postinflammatory hyperpigmentation in dogs. https://www.msdvetmanual.com/integumentary-system/acanthosis-nigricans-and-postinflammatory-hyperpigmentation (darkening can appear during active disease or as the skin heals)
  15. Today's Veterinary Practice. Recurring otitis externa. 2025. https://todaysveterinarypractice.com/wp-content/uploads/sites/4/2025/10/TVP-2025-1112_Recurring-Otitis-Externa.pdf (a short steroid course can open a swollen canal enough for exam, cleaning and drops)
  16. Veterinary Ireland Journal. Otitis externa in dogs. Focus article, July 2020. https://www.veterinaryirelandjournal.com/focus/174-otitis-externa-in-dogs (chronic inflammation narrows the canal and can become irreversible; total ear canal ablation for end-stage ears)
  17. Clinician's Brief. Pseudomonas otitis infection in cats and dogs. https://www.cliniciansbrief.com/article/pseudomonas-otitis-infection-cats-and-dogs (chronic ear thickening, narrowing and calcification). See also Chapter 7 references.
  18. Author's clinic pricing, Cypress, Texas, 2026, and Hearthstone Animal Clinic, Cypress dog allergies page; Vetster and US online pharmacy prices, 2026. Estimates only, for a dog of about 55 pounds. Yearly figures are the monthly ranges times 12; the year-one reset box adds exam, skin and ear cytology, infection medicines, 12 months of flea chews, shampoo and fish oil, a food trial, a year of Apoquel or Cytopoint, 3 or 4 rechecks and one blood panel with urinalysis, rounded to the nearest $100.
  19. UTHealth Houston, Department of Otorhinolaryngology. Allergy update. 2010. https://med.uth.edu/orl/2010/11/28/allergy-update/ ; and Aspire Allergy & Sinus. How to treat your allergies in Houston, TX. https://www.aspireallergy.com/blog/how-to-treat-your-allergies-houston-tx (Houston pollen calendar: trees from January, grasses from March, ragweed mid-August to first frost; human allergy sources, not dog studies)

Chapter 12: The home team: baths, wipes, fish oil and the cone of shame

  1. Olivry T, DeBoer DJ, Favrot C, Jackson HA, Mueller RS, Nuttall T, Prélaud P; International Committee on Allergic Diseases of Animals. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6. PMCID PMC4537558. (regular bathing with a mild, non-irritating shampoo for flares and long-term care; fatty acids; small, mostly preventive role for antihistamines)
  2. Löflath A, von Voigts-Rhetz A, Jaeger K, Schmid M, Kuechenhoff H, Mueller RS. The efficacy of a commercial shampoo and whirlpooling in the treatment of canine pruritus: a double-blinded, randomized, placebo-controlled study. Vet Dermatol. 2007;18(6):427-431. (22 dogs; a weekly anti-itch shampoo lowered itch more than water alone)
  3. Negre A, Bensignor E, Guillot J. Evidence-based veterinary dermatology: a systematic review of interventions for Malassezia dermatitis in dogs. Vet Dermatol. 2009;20(1):1-12. (2% chlorhexidine plus 2% miconazole shampoo twice weekly has the best evidence)
  4. Bond R, Morris DO, Guillot J, Bensignor EJ, Robson D, Mason KV, Kano R, Hill PB. Biology, diagnosis and treatment of Malassezia dermatitis in dogs and cats: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology. Vet Dermatol. 2020;31(1):28-74. doi:10.1111/vde.12809 (yeast favors warm, moist, folded skin; topical chlorhexidine and miconazole)
  5. Loeffler A, Cain CL, Ferrer L, Nishifuji K, et al. Antimicrobial use guidelines for canine pyoderma by the International Society for Companion Animal Infectious Diseases (ISCAID). Vet Dermatol. 2025;36(3):234-282. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12058580/ (2 to 4% chlorhexidine is the best-studied topical for surface and superficial skin infection)
  6. US Food and Drug Administration. Skin protectant drug products for over-the-counter human use, 21 CFR Part 347. (colloidal oatmeal is listed as a human skin protectant; no controlled dog trial of oatmeal shampoo alone for itch was found)
  7. McDonnell G, Russell AD. Antiseptics and disinfectants: activity, action, and resistance. Clin Microbiol Rev. 1999;12(1):147-179. doi:10.1128/CMR.12.1.147 (how chlorhexidine binds to and damages microbial cell surfaces)
  8. Nextmune. "Why maximising topical therapy is important." Veterinary blog (industry source). https://nextmune.com/vet/blog-news/why-maximising-topical-therapy-is-important (5 to 10 minutes of contact time for medicated shampoos; no trial has tested contact time on its own)
  9. Today's Veterinary Practice. Clinic resource: ear cleaners for otitis externa. 2017. https://todaysveterinarypractice.com/wp-content/uploads/sites/4/2022/02/TVP-2017-0506_Clinic-Resource_Ear-Cleaners-Otitis_04.pdf (maintenance cleaning once or twice weekly after an infection clears; avoid over-cleaning)
  10. Today's Veterinary Practice. Topical therapy for otitis externa. https://todaysveterinarypractice.com/dermatology/topical-therapy-for-otitis-externa/ (excessive cleaning can keep an ear infection going)
  11. Fujimura M, Nakatsuji Y, Fujiwara S, Rème C, Gatto H. Spot-on skin lipid complex as an adjunct therapy in dogs with atopic dermatitis: an open pilot study. Vet Med Int. 2011;2011:281846. doi:10.4061/2011/281846 (8 dogs, open study; about a 26% drop in lesion scores at 6 weeks)
  12. Blaskovic M, Rosenkrantz W, Neuber A, Sauter-Louis C, Mueller RS. The effect of a spot-on formulation containing polyunsaturated fatty acids and essential oils on dogs with atopic dermatitis. Vet J. 2014;199(1):39-43. https://epub.ub.uni-muenchen.de/53023 (26 dogs, double-blind; no significant difference from placebo)
  13. Genovese AG, McLean MK, Khan SA. Adverse reactions from essential oil-containing natural flea products exempted from Environmental Protection Agency regulations in dogs and cats. J Vet Emerg Crit Care. 2012;22(4):470-475. PMID 22805458. (serious reactions possible even when used as labeled)
  14. Lenox CE, Bauer JE. Potential adverse effects of omega-3 fatty acids in dogs and cats. J Vet Intern Med. 2013;27(2):217-226. doi:10.1111/jvim.12033 (GI upset, platelet function, wound healing, weight gain; effects likely dose-dependent)
  15. Mueller RS, Fieseler KV, Fettman MJ, Zabel S, Rosychuk RAW, Ogilvie GK, Greenwalt TL. Effect of omega-3 fatty acids on canine atopic dermatitis. J Small Anim Pract. 2004;45(6):293-297. PMID 15206474. (29 dogs, 10 weeks; the EPA plus DHA amount used, about 85 mg/kg/day, is far above typical chew servings)
  16. Sævik BK, Bergvall K, Holm BR, Saijonmaa-Koulumies LE, Hedhammar Å, Larsen S, Kristensen F. A randomized, controlled study to evaluate the steroid sparing effect of essential fatty acid supplementation in the treatment of canine atopic dermatitis. Vet Dermatol. 2004;15(3):137-145. (60 dogs, 12 weeks; fatty acids lowered the prednisolone dose needed)
  17. Today's Veterinary Practice. "Fish oil dosing in pet diets and supplements." May/June 2020. https://mydigitalpublication.com/article/Fish+Oil+Dosing+in+Pet+Diets+and+Supplements/3655111/657682/article.html
  18. Hsiao YH, Chen C, Willemse T. Effects of cetirizine in dogs with chronic atopic dermatitis: a randomized, double blind, placebo-controlled trial. J Vet Sci. 2016;17(4):549-554. PMCID PMC5204033. (50 dogs, 14 days; no significant difference in itch versus placebo)
  19. Zoetis. TEMARIL-P (trimeprazine tartrate and prednisolone) tablets, package insert. https://image.chewy.com/is/content/catalog/146300_PackageInsert_TemarilP._V1526682125_.pdf
  20. Merck Veterinary Manual, professional version. Toxicoses from human over-the-counter drugs: decongestants (pseudoephedrine, phenylephrine).
  21. US Food and Drug Administration. "Paws off xylitol; it's a dog-gone danger!" Consumer update.
  22. Arlian LG, Platts-Mills TAE. The biology of dust mites and the remediation of mite allergens in allergic disease. J Allergy Clin Immunol. 2001;107(3 Suppl):S406-S413. (human allergy review; hot-water washing of bedding)
  23. Arlian LG, Neal JS, Morgan MS, Vyszenski-Moher DL, Rapp CM, Alexander AK. Reducing relative humidity is a practical way to control dust mites and their allergens in homes in temperate climates. J Allergy Clin Immunol. 2001;107(1):99-104. (human homes; relative humidity below about 50%)
  24. MedlinePlus (US National Library of Medicine). Allergies, asthma, and pollen. Patient instructions. https://medlineplus.gov/ency/patientinstructions/000489.htm (pollen counts run highest in the early morning and on dry, hot, windy days)
  25. Author's clinic pricing, Cypress, Texas, 2026. Estimates for shampoo, wipes, ear cleaner, fish oil, antihistamines, barrier spot-ons, shirts, socks, boots and e-collars; local and online prices vary.

Chapter 13: Steroids: the old reliable

  1. Olivry T, Mueller RS. Evidence-based veterinary dermatology: a systematic review of the pharmacotherapy of canine atopic dermatitis. Vet Dermatol. 2003;14(3):121-146. PMID 12791047. (40 trials, 1,607 dogs; good evidence for oral steroids and cyclosporine)
  2. Olivry T, DeBoer DJ, Favrot C, Jackson HA, Mueller RS, Nuttall T, Prélaud P; International Committee on Allergic Diseases of Animals. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6. PMCID PMC4537558. (long-acting injectable steroids not recommended unless oral treatment is impossible)
  3. Merck Veterinary Manual, professional version. Hormonal therapy for integumentary disease. https://www.merckvetmanual.com/pharmacology/systemic-pharmacotherapeutics-of-the-integumentary-system/hormonal-therapy-for-integumentary-disease (steroid side effects; oral dosing preferred because it can be adjusted and tapered; methylprednisolone acetate can affect adrenal function for up to 10 weeks)
  4. Gadeyne C, Little P, King VL, Edwards N, Davis K, Stegemann MR. Efficacy of oclacitinib (Apoquel) compared with prednisolone for the control of pruritus and clinical signs associated with allergic dermatitis in client-owned dogs in Australia. Vet Dermatol. 2014;25(6):512-518, e86. PMCID PMC4282467. (123 dogs; both drugs worked within 4 hours; authors employed by Zoetis)
  5. Long-term glucocorticoid adverse effects in 40 dogs referred to a dermatology clinic. Japanese Journal of Veterinary Dermatology, vol. 10, no. 2 (J-STAGE). (27 of 40 dogs had side effects)
  6. Torres SMF, et al. Frequency of urinary tract infection among dogs with pruritic disorders receiving long-term glucocorticoid treatment. J Am Vet Med Assoc. 2005;227(2):239-243.
  7. Merck Veterinary Manual, professional version. Metabolic diseases affecting the liver in small animals. https://www.merckvetmanual.com/digestive-system/hepatic-diseases-of-small-animals/metabolic-diseases-affecting-the-liver-in-small-animals (steroid liver changes and the steroid-induced alkaline phosphatase in dogs)
  8. Author's clinical summary of standard veterinary practice for long-term steroid use: side effects including stomach ulcers, pancreatitis and ligament injury; reasons not to use them (diabetes, active infection, eye or stomach ulcers, pancreatitis, an NSAID on board); the lowest effective dose every other day for maintenance; bloodwork and urinalysis with culture every 6 to 12 months. See also notes 2 and 3.
  9. Fennis EEM, van Damme CMM, Schlotter YM, et al. Efficacy of subcutaneous allergen immunotherapy in atopic dogs: a retrospective study of 664 cases. Vet Dermatol. 2022;33(4):321-e75. PMCID PMC9544551. (dogs also on long-term oral steroids did worse on allergy shots, 38.5% success)
  10. Clinician's Brief. "Top 7 drug classes to be tapered before discontinuation." Fall 2024. https://www.qgdigitalpublishing.com/article/Top+7+Drug+Classes+to+Be+Tapered+Before+Discontinuation/4822851/827717/article.html (steroids given daily for more than 2 to 3 weeks should be tapered)
  11. Kemppainen RJ, Lorenz MD, Thompson FN. Adrenocortical suppression in the dog after a single dose of methylprednisolone acetate. Am J Vet Res. 1981;42(5):822-824. (adrenal suppression after one long-acting injection)
  12. Zoetis. TEMARIL-P (trimeprazine tartrate and prednisolone) tablets, package insert. https://image.chewy.com/is/content/catalog/146300_PackageInsert_TemarilP._V1526682125_.pdf ; https://vetlabel.com/lib/vet/meds/temaril-p/ (labeled for itch and for cough)
  13. Christopher S. Avoiding GI ulceration: practical tips for NSAID and corticosteroid use in canines. Today's Veterinary Practice. https://todaysveterinarypractice.com/internal-medicine/avoiding-gi-ulceration-practical-tips-for-nsaid-and-corticosteroid-use-in-canines/ (an NSAID plus a steroid raises the risk of severe stomach ulcers)
  14. Author's clinic pricing, Cypress, Texas, 2026. Estimates for prednisone, Temaril-P, injections, exams and urine cultures; your clinic and city will vary.
  15. Author's clinic pricing, Cypress, Texas, 2026. Estimate for a chemistry panel plus urinalysis.

Chapter 14: Apoquel: the daily pill (and the cancer question)

  1. Zoetis. Apoquel consumer safety statement, as used in US television advertising and on the Apoquel product site. https://zoetis-apoquel-live.cphostaccess.com/safety ; Zoetis, "Zoetis debuts first-ever national TV campaigns." https://www.zoetis.com/news-and-insights/featured-stories/zoetis-debuts-first-ever-national-tv-campaigns
  2. Owner reports (anecdotal): JustAnswer, https://www.justanswer.com/dog-health/r5siu-dog-diagnosed-cancer-lining-blood.html ; 2ndChance, Apoquel owner feedback, https://vetspace.2ndchance.info/dog-owner-feedback-from-apoquel-users/ ; PetCareRx Apoquel reviews, https://www.petcarerx.com/apoquel/25153/reviews/1 (an owner who stopped after a TV ad; owner costs of about $85 and $122 a month)
  3. Zoetis. "FDA Approves APOQUEL (oclacitinib tablet) to Control Itch and Inflammation in Allergic Dogs." Press release, May 16, 2013 (NADA 141-345). https://www.aol.com/2013-05-16-fda-approves-apoquel-oclacitinib-tablet-to-control.html ; FDA Freedom of Information summary, https://fda.gov/media/113909/download (approved May 2013)
  4. Zoetis. "Zoetis Announces FDA Approval of Apoquel Chewable (oclacitinib chewable tablet)." Press release, June 13, 2023. https://news.zoetis.com/press-releases/press-release-details/2023/Zoetis-Announces-FDA-Approval-of-Apoquel-Chewable-oclacitinib-chewable-tablet-for-Control-of-Pruritus-Associated-With-Allergic-Dermatitis-and-Control-of-Atopic-Dermatitis-in-Dogs/default.aspx (approved June 2023; more than 13 million US dogs treated in the prior decade)
  5. Gonzales AJ, Bowman JW, Fici GJ, et al. Oclacitinib (APOQUEL) is a novel Janus kinase inhibitor with activity against cytokines involved in allergy. J Vet Pharmacol Ther. 2014;37(4):317-324. doi:10.1111/jvp.12101
  6. Gadeyne C, Little P, King VL, Edwards N, Davis K, Stegemann MR. Efficacy of oclacitinib (Apoquel) compared with prednisolone for the control of pruritus and clinical signs associated with allergic dermatitis in client-owned dogs in Australia. Vet Dermatol. 2014;25(6):512-518, e86. PMCID PMC4282467. (123 dogs; itch relief within 4 hours; authors employed by Zoetis)
  7. Cosgrove SB, Wren JA, Cleaver DM, Martin DD, Walsh KF, Harfst JA, Follis SL, King VL, Boucher JF, Stegemann MR. Efficacy and safety of oclacitinib for the control of pruritus and associated skin lesions in dogs with canine allergic dermatitis. Vet Dermatol. 2013;24(5):479-e114. PMID 23829933. (436 dogs; itch relief within 24 hours)
  8. Olivry T, DeBoer DJ, Favrot C, Jackson HA, Mueller RS, Nuttall T, Prélaud P; International Committee on Allergic Diseases of Animals. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6. PMCID PMC4537558.
  9. Zoetis. APOQUEL (oclacitinib tablet) and APOQUEL Chewable US prescribing information. https://vetlabel.com/lib/vet/meds/apoquel/ ; https://vetlabel.com/lib/vet/meds/apoquel-chewable/ ; https://www.poison.org/-/media/files/pdf-for-article-dowloads-and-refs/apoquel-prescribing-information.pdf (dosing, contraindications, warnings, field-study side effects and safety studies)
  10. Forster S, Boegel A, Despa S, Trout C, King S. Comparative efficacy and safety of ilunocitinib and oclacitinib for the control of pruritus and associated skin lesions in dogs with atopic dermatitis. Vet Dermatol. 2025. doi:10.1111/vde.13319. (Elanco-funded; authors employed by Elanco)
  11. Zoetis. Apoquel Summary of Product Characteristics, UK Veterinary Medicines Directorate. https://www.vmd.defra.gov.uk/ProductInformationdatabase/files/SPC_Documents/SPC_2155229.PDF (puppies given 3 times the maximum dose for 84 days responded adequately to distemper and parvo vaccines, less well to parainfluenza and rabies)
  12. Lancellotti BA, Angus JC, Edginton HD, Rosenkrantz WS. Age- and breed-matched retrospective cohort study of malignancies and benign skin masses in 660 dogs with allergic dermatitis treated long-term with versus without oclacitinib. J Am Vet Med Assoc. 2020;257(5):507-516. Summary: Olivry T, Nextmune "Point of View," February 2021, https://nextmune.com/vet/blog-news/dr.-thierry-olivrys-point-of-view-february-2021 (339 treated dogs and 321 matched controls followed more than 2 years; no difference in tumors)
  13. Common veterinary practice for oclacitinib monitoring: baseline blood count, chemistry and urinalysis, rechecked every 6 to 12 months and whenever the dog is unwell. The US label recommends periodic monitoring without a set interval; see note 9.
  14. VetLens. "Apoquel for dogs." Owner-facing veterinary blog. https://www.vetlens.com/blog/apoquel-for-dogs (more sleep once the itch is controlled)
  15. Cosgrove SB, Cleaver DM, King VL, et al. Long-term compassionate use of oclacitinib in dogs with atopic and allergic skin disease: safety, efficacy and quality of life. Vet Dermatol. 2015;26(3):171-179, e35. (247 dogs, up to 630 days; open-label, company-sponsored)
  16. Michels GM, Ramsey DS, Walsh KF, et al. A blinded, randomized, placebo-controlled, dose determination trial of lokivetmab (ZTS-00103289), a caninized, anti-canine IL-31 monoclonal antibody in client owned dogs with atopic dermatitis. Vet Dermatol. 2016;27(6):478-e129.
  17. Vetster. "Zenrelia vs. Apoquel." https://vetster.com/en/wellness/zenrelia-vs-apoquel-for-dogs (first-month cost for a 50 lb dog). Author's clinic pricing, Cypress, Texas, 2026. Bloodwork and urinalysis as in Chapter 13.
  18. WebVet. "Oclacitinib for Dogs." https://www.webvet.com/oclacitinib-for-dogs/ (US patent protection runs to about 2030)
  19. Costco Pharmacy. Zoetis Apoquel information page. https://www.costco.com/cmpp-zoetis-apoquel-information.html

Chapter 15: Cytopoint: the shot that catches the message

  1. Zoetis. CYTOPOINT (lokivetmab) US package insert. https://www.drugs.com/vet/cytopoint.html (an antibody that binds canine IL-31 so it can't reach its receptor on itch nerves). See also Chapter 2, references on IL-31.
  2. Michels GM, Walsh KF, Kryda KA, Mahabir SP, Walters RR, Hoevers JD, Martinon OM. A blinded, randomized, placebo-controlled trial of the safety of lokivetmab (ZTS-00103289), a caninized anti-canine IL-31 monoclonal antibody in client-owned dogs with atopic dermatitis. Vet Dermatol. 2016;27(6):505-e136. (245 dogs; side effects similar to placebo; anti-drug antibodies in 2.5% of treated dogs; Zoetis-run trial)
  3. Zoetis. "How it works: Cytopoint." https://www.zoetis.com/news-and-insights/blog/posts/how-it-works-cytopoint (onset within 24 hours; 4 to 8 weeks per injection)
  4. Zoetis. "Zoetis Receives New Allergic Dermatitis Indication for Cytopoint." Press release, 2018. https://news.zoetis.com/press-releases/press-release-details/2018/Zoetis-Receives-New-Allergic-Dermatitis-Indication-for-Cytopoint/ (dogs of any age; can be used with many common medications, including vaccines)
  5. Kasper B, Zablotski Y, Mueller RS. Long-term use of lokivetmab in dogs with atopic dermatitis. Vet Dermatol. 2024;35(6):683-693. PMC11938560. https://epub.ub.uni-muenchen.de/126157/ (150 dogs at the University of Munich; 77% success; side effects in 8%, mostly mild stomach upset or tiredness)
  6. European Medicines Agency. Cytopoint (lokivetmab): EPAR and Summary of Product Characteristics. https://www.ema.europa.eu/en/documents/overview/cytopoint-epar-medicine-overview_en.pdf ; UK VMD product information: https://www.vmd.defra.gov.uk/productinformationdatabase/files/QRD_Documents/QRD-Auth_2169259.PDF (anti-drug antibodies are uncommon; half-life about 16 days)
  7. Wyndly. Cytopoint injection price. https://www.wyndly.com/blogs/learn/cytopoint-injection-price ; ThePricer. Cytopoint injection cost. https://www.thepricer.org/cytopoint-injection-cost/ Author's clinic pricing, Cypress, Texas, 2026. (weight tiers and yearly totals are the author's arithmetic from these ranges)
  8. Zoetis. "Zoetis Receives USDA License for CYTOPOINT." Press release, December 21, 2016. https://news.zoetis.com/press-releases/press-release-details/2016/Zoetis-Receives-USDA-License-for-CYTOPOINT/ ; USDA conditional license, August 3, 2015 (as Canine Atopic Dermatitis Immunotherapeutic), FiercePharma: https://www.fiercepharma.com/regulatory/usda-grants-conditional-license-to-zoetis-for-canine-anti-itch-therapy
  9. Fleck TJ, Norris LR, Mahabir S, et al. Onset and duration of action of lokivetmab in a canine model of IL-31 induced pruritus. Vet Dermatol. 2021. https://pmc.ncbi.nlm.nih.gov/articles/PMC9291138 (24 Beagles; itch reduced from about 3 hours, lasting 42 days at the label dose)
  10. Michels GM, Ramsey DS, Walsh KF, Martinon OM, Mahabir SP, Hoevers JD, Walters RR, Dunham SA. A blinded, randomized, placebo-controlled, dose determination trial of lokivetmab (ZTS-00103289), a caninized, anti-canine IL-31 monoclonal antibody in client owned dogs with atopic dermatitis. Vet Dermatol. 2016;27(6):478-e129. (211 dogs; itch reduced through day 49 versus placebo; Zoetis-run trial)
  11. Moyaert H, Van Brussel L, Borowski S, Escalada M, Mahabir SP, Walters RR, Stegemann MR. A blinded, randomized clinical trial evaluating the efficacy and safety of lokivetmab compared to ciclosporin in client-owned dogs with atopic dermatitis. Vet Dermatol. 2017;28(6):593-e145. (274 dogs; itch reduction about 52% with lokivetmab versus 44% with cyclosporine at day 28)
  12. Gonzales AJ, Humphrey WR, Messamore JE, et al. Interleukin-31: its role in canine pruritus and naturally occurring canine atopic dermatitis. Vet Dermatol. 2013;24(1):48-e12. PMID 23331679. (IL-31 detectable in the blood of 57% of dogs with atopic dermatitis)
  13. Zoetis. CYTOPOINT (lokivetmab) US package insert. https://www.drugs.com/vet/cytopoint.html (uncommon vomiting, tiredness and injection-site discomfort; broken down like a normal protein rather than by the liver or kidneys)
  14. WebVet. "Lokivetmab for dogs and cats." https://www.webvet.com/lokivetmab-for-dogs-and-cats/ (anti-drug antibodies rarely affected how well it worked and were not linked to allergic reactions)
  15. Bachtel JC, Snidow M, et al. Efficacy of combination oclacitinib and lokivetmab therapies after monotherapeutic failure in 44 dogs: a retrospective study. Vet Dermatol. Published online 2025. doi:10.1111/vde.70034. PMID 41189387. (27 of 44 dogs, 61%, responded to the combination after failing each drug alone)
  16. Elanco. "Befrena USDA approval." Press release, December 31, 2025. https://elanco.com/us/newsroom/press-releases/befrena-usda-approval ; "Befrena launch," May 2026, https://elanco.com/us/newsroom/press-releases/befrena-launch ; dvm360, January 2, 2026, https://www.dvm360.com/view/usda-approves-new-anti-il31-monoclonal-antibody-injection (anti-IL-31 antibody; 6 to 8 week dosing; dogs of any age)

Chapter 16: Zenrelia and the new kids

  1. US Food and Drug Administration. "FDA Approves New Treatment for Allergic Skin Conditions in Dogs." CVM Updates, September 2024. https://www.fda.gov/animal-veterinary/cvm-updates/fda-approves-new-treatment-allergic-skin-conditions-dogs ; dvm360, https://www.dvm360.com/view/zenrelia-receives-fda-approval (Zenrelia approved September 19, 2024, for dogs at least 12 months old)
  2. Merck Animal Health. "FDA Approves NUMELVI (atinvicitinib tablets) for Dogs from Merck Animal Health, the First and Only Second Generation Janus Kinase (JAK) Inhibitor for the Control of Pruritus Associated with Allergic Dermatitis." Business Wire, February 25, 2026. https://www.merck-animal-health.com/news-and-insights/news-releases/fda-approves-numelvi-atinvicitinib-tablets-for-dogs-from-merck-animal-health-the-first-and-only-second-generation-janus-kinase-jak-inhibitor-for-the-control-of-pruritus-associat/ ; dvm360, https://www.dvm360.com/view/fda-approves-first-and-only-second-generation-janus-kinases-inhibitor (dogs 6 months and older; available to US clinics spring 2026)
  3. Elanco Animal Health. "Befrena USDA approval." Press release, December 2025. https://elanco.com/us/newsroom/press-releases/befrena-usda-approval ; Veterinary Practice News, "USDA approves drug for canine allergic and atopic dermatitis," https://www.veterinarypracticenews.com/usda-approves-befrena-canine-allergic-atopic-dermatitis/ ; dvm360, January 2, 2026, https://www.dvm360.com/view/usda-approves-new-anti-il31-monoclonal-antibody-injection (approved December 31, 2025; 6 to 8 week interval)
  4. Forster S, Boegel A, Despa S, Trout C, King S. Comparative efficacy and safety of ilunocitinib and oclacitinib for the control of pruritus and associated skin lesions in dogs with atopic dermatitis. Vet Dermatol. 2025. doi:10.1111/vde.13319. (338 dogs, 25 clinics, 4 countries, up to 112 days; Elanco-funded)
  5. Elanco. ZENRELIA (ilunocitinib tablets) US package insert, revised September 2025. https://vetlabel.com/lib/vet/meds/zenrelia/ ; FDA Freedom of Information Summary, https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/15865 (boxed vaccine warning: stop at least 28 days to 3 months before vaccination and for at least 28 days after; vomiting, diarrhea and lethargy the most common side effects)
  6. Merck Animal Health. NUMELVI (atinvicitinib tablets) US product label. https://www.merck-animal-health-usa.com/downloads/numelvi-product-label ; FDA Freedom of Information Summary, https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/18155 (not evaluated in a field study beyond 28 days; no vaccine-timing warning)
  7. Zoetis. "FDA Approves APOQUEL (oclacitinib tablet) to Control Itch and Inflammation in Allergic Dogs." Press release, May 16, 2013 (NADA 141-345). https://www.aol.com/2013-05-16-fda-approves-apoquel-oclacitinib-tablet-to-control.html (approved May 2013)
  8. Zoetis. "Zoetis Receives USDA License for CYTOPOINT." Press release, December 21, 2016. https://news.zoetis.com/press-releases/press-release-details/2016/Zoetis-Receives-USDA-License-for-CYTOPOINT/ ; USDA conditional license, August 3, 2015 (as Canine Atopic Dermatitis Immunotherapeutic), FiercePharma: https://www.fiercepharma.com/regulatory/usda-grants-conditional-license-to-zoetis-for-canine-anti-itch-therapy
  9. Elanco. Zenrelia (ilunocitinib) European Commission approval, July 24, 2025. BioPharmaWatch, https://www.biopharmawatch.com/news/ELAN/elanco-secures-approval-of-zenrelia-ilunocitinib-in-the-european-union-eu-launching-innova-elan-20250724 ; dvm360, https://www.dvm360.com/view/european-commission-approves-zenrelia
  10. Merck Animal Health. "European Commission Approves NUMELVI (atinvicitinib) Tablets for Dogs." July 24, 2025. https://www.merck-animal-health.com/blog/2025/07/24/european-commission-approves-numelvi-atinvicitinib-tablets-for-dogs/
  11. Elanco. "Elanco Launches Befrena (tirnovetmab), New Anti-IL-31 Monoclonal Antibody." Press release, May 2026. https://elanco.com/us/newsroom/press-releases/befrena-launch ; AAHA, "Befrena launches for treatment of allergic dermatitis in dogs," https://www.aaha.org/trends-magazine/publications/befrena-launches-for-treatment-of-allergic-dermatitis-in-dogs/ ; MyVetCandy, May 18, 2026, https://www.myvetcandy.com/news/2026/5/18/elanco-launches-befrena-a-new-anti-il-31-monoclonal-antibody-for-canine-dermatology (onset within 24 hours; 6 to 8 week duration; no age or weight limits)
  12. See Chapter 2, "JAK: the switchboard inside the cell."
  13. US Food and Drug Administration. Freedom of Information Summary, Zenrelia (ilunocitinib). https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/15865 ; UK Summary of Product Characteristics, https://www.vmd.defra.gov.uk/ProductInformationDatabase/files/SPC_Documents/SPC_3061994.PDF (ilunocitinib blocks JAK1, JAK2 and TYK2)
  14. Zoetis. APOQUEL (oclacitinib tablet) US prescribing information. https://vetlabel.com/lib/vet/meds/apoquel/ (dogs at least 12 months old; twice daily up to 14 days, then once daily)
  15. See Chapter 14 (Apoquel): selectivity, the step-down from twice to once daily, and the long-term tumor data.
  16. US Food and Drug Administration. "Dear Veterinarian Letter Regarding Important Safety Information Associated with Use of Zenrelia (ilunocitinib)." https://www.fda.gov/animal-veterinary/product-safety-information/dear-veterinarian-letter-regarding-important-safety-information-associated-use-zenrelia-ilunocitinib (in a lab study at 3 times the label dose, some dogs responded poorly to distemper and rabies vaccines)
  17. Elanco. "Elanco Announces FDA Approves Improved Zenrelia (ilunocitinib tablets) Label, Removing Vaccine-Induced Disease Language." Press release, September 23, 2025. https://elanco.com/us/newsroom/press-releases/elanco-announces-FDA-update-of-zenrelia-label ; AAHA, "FDA approves removal of some vaccine-related warnings for Zenrelia label," https://www.aaha.org/trends-magazine/publications/fda-approves-removal-of-some-vaccine-related-warnings-for-zenrelia-label/ ; dvm360, "FDA approves updated US label for Zenrelia," https://www.dvm360.com/view/fda-approves-updated-us-label-for-zenrelia ; study report: "Response to primary canine core vaccination in 10-month-old seronegative dogs treated with three times the recommended therapeutic dose of ilunocitinib tablets," https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12257700/
  18. Ellis J, Marziani E, Aziz C, et al. 2022 AAHA Canine Vaccination Guidelines. J Am Anim Hosp Assoc. 2022;58(5):213-230. (core boosters a year after the puppy series, then at intervals; leptospirosis yearly for at-risk dogs)
  19. Texas Department of State Health Services. Rabies vaccination requirements for dogs and cats, Texas Administrative Code, Title 25, §169.29. https://www.dshs.texas.gov/rabies (vaccinate by 16 weeks, booster 12 months later, then per the vaccine's 1-year or 3-year label)
  20. Zoetis. CYTOPOINT (lokivetmab) US package insert. https://www.drugs.com/vet/cytopoint.html (dogs of any age; may be used with many common medications including vaccines). See also Chapter 15.
  21. See Chapter 5, the vaccine theory and the "as needed, not more than needed" guidance.
  22. Elanco. Zenrelia approval investor call slides, September 2024 (industry source). https://s1.q4cdn.com/466533431/files/doc_presentations/2024/09/ELAN_Zenrelia-Approval-Call-Slides.pdf (launch list price about 20% below the older JAK pill)
  23. Vetster. "Zenrelia vs. Apoquel." https://vetster.com/en/wellness/zenrelia-vs-apoquel-for-dogs (50 lb dog: Zenrelia about $70 to $130 a month). Author's clinic pricing, Cypress, Texas, 2026. (Apoquel maintenance range)
  24. Merck Animal Health. NUMELVI product overview (marketing figure). https://www.merck-animal-health-usa.com/downloads/numelvi-product-overview (more than 82% of dogs had a significant itch improvement within 1 week)
  25. No published US list price for Numelvi as of October 2026. Retail listings: Tractor Supply, https://www.tractorsupply.com/tsc/product/numelvi-atinvicitinib-tablets-for-dogs ; Banfield Pet Hospital shop, https://shop.banfield.com/numelvi-tablets.html
  26. See Chapter 15 (Cytopoint), including anti-drug antibodies.
  27. Clinician's Brief. "Another New Treatment Option for Dogs With Allergic Dermatitis." https://www.cliniciansbrief.com/article/tirnovetmab-allergic-dermatitis-dogs (tirnovetmab safe and effective in 2 clinical trials; no peer-reviewed field data published as of October 2026)
  28. No published US price for Befrena was available as of October 2026.
  29. European Medicines Agency. Cytopoint (lokivetmab): EPAR and Summary of Product Characteristics. https://www.ema.europa.eu/en/documents/overview/cytopoint-epar-medicine-overview_en.pdf (anti-drug antibodies are uncommon)
  30. Merck Veterinary Manual, professional version. Hormonal therapy for integumentary disease. https://www.merckvetmanual.com/pharmacology/systemic-pharmacotherapeutics-of-the-integumentary-system/hormonal-therapy-for-integumentary-disease (steroid side effects)
  31. Novartis Animal Health / Elanco. ATOPICA (cyclosporine, modified) capsules for dogs, US package insert. https://www.drugs.com/pro/atopica.html ; Federal Register notice, https://www.govinfo.gov/content/pkg/FR-2003-09-19/pdf/03-23944.pdf (approved August 15, 2003, NADA 141-218)
  32. Lancellotti BA, Angus JC, Edginton HD, Rosenkrantz WS. Age- and breed-matched retrospective cohort study of malignancies and benign skin masses in 660 dogs with allergic dermatitis treated long-term with versus without oclacitinib. J Am Vet Med Assoc. 2020;257(5):507-516. (339 treated dogs and 321 matched controls followed more than 2 years)
  33. US Food and Drug Administration, Center for Veterinary Medicine. "From an Idea to the Marketplace: The Journey of an Animal Drug through the Approval Process." https://www.fda.gov/animal-veterinary/resources-you/idea-marketplace-journey-animal-drug-through-approval-process (what approval requires: evidence of effectiveness, target animal safety, labeling)
  34. US Food and Drug Administration. "How to Report Animal Drug and Device Side Effects and Product Problems." https://www.fda.gov/animal-veterinary/report-problem/how-report-animal-drug-and-device-side-effects-and-product-problems
  35. Zoetis. "Zoetis Announces FDA Approval of Apoquel Chewable (oclacitinib chewable tablet)." Press release, June 13, 2023. https://news.zoetis.com/press-releases/press-release-details/2023/Zoetis-Announces-FDA-Approval-of-Apoquel-Chewable-oclacitinib-chewable-tablet-for-Control-of-Pruritus-Associated-With-Allergic-Dermatitis-and-Control-of-Atopic-Dermatitis-in-Dogs/default.aspx (more than 13 million US dogs treated with Apoquel in the prior decade)
  36. Hanley JA, Lippman-Hand A. If nothing goes wrong, is everything all right? Interpreting zero numerators. JAMA. 1983;249(13):1743-1745. (the "rule of three": with 0 events in n subjects, the 95% upper limit is about 3/n)
  37. US Food and Drug Administration, Center for Veterinary Medicine. ProHeart 6 (moxidectin) history: approved 2001; voluntary recall at FDA's request in September 2004 over adverse event reports, including deaths; returned to market in 2008 under a risk minimization program. See also Chapter 6 references.
  38. See Chapter 6, the ProHeart section.
  39. See Chapter 7 (infections as the usual reason a drug "stops working") and Chapters 6, 8 and 9 (fleas and the food trial).
  40. US Department of Agriculture, APHIS Center for Veterinary Biologics. Adverse event reporting for veterinary biologics. https://www.aphis.usda.gov/veterinary-biologics/adverse-event-reporting
  41. Wyndly. Cytopoint injection price. https://www.wyndly.com/blogs/learn/cytopoint-injection-price ; ThePricer. Cytopoint injection cost. https://www.thepricer.org/cytopoint-injection-cost/ Author's clinic pricing, Cypress, Texas, 2026.

Chapter 17: The long game: cyclosporine and allergy shots

  1. Novartis Animal Health / Elanco. ATOPICA (cyclosporine, modified) capsules for dogs, US package insert. NADA 141-218, approved August 15, 2003. https://www.drugs.com/vet/atopica.html ; https://image.chewy.com/is/content/catalog/146107_PackageInsert._V1542385013_.pdf (once daily for 30 days, then taper to every other day or twice weekly; vomiting and diarrhea most common; no live vaccines during treatment; lesion scores 45% better vs 9% worse on placebo at 30 days)
  2. Fennis EEM, van Damme CMM, Schlotter YM, et al. Efficacy of subcutaneous allergen immunotherapy in atopic dogs: a retrospective study of 664 cases. Vet Dermatol. 2022;33(4):321-e75. doi:10.1111/vde.13075. PMCID PMC9544551. (59.9% of dogs at least 50% improved after 9 or more months; dogs with regular rechecks did better)
  3. Olivry T, DeBoer DJ, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6. (allergen immunotherapy as the only treatment that can change the course of the disease)
  4. Olivry T, Mueller RS. Evidence-based veterinary dermatology: a systematic review of the pharmacotherapy of canine atopic dermatitis. Vet Dermatol. 2003;14(3):121-146. PMID 12791047.
  5. Steffan J, Favrot C, Mueller R. A systematic review and meta-analysis of the efficacy and safety of cyclosporin for the treatment of atopic dermatitis in dogs. Vet Dermatol. 2006;17(1):3-16.
  6. Eisenschenk MC, Hensel P, Saridomichelakis MN, Tamamoto-Mochizuki C, Pucheu-Haston CM, Santoro D. Introduction to the ICADA 2023 canine atopic dermatitis pathogenesis review articles and updated definition. Vet Dermatol. 2024;35(1). PMID 38095285. (atopic dermatitis described as predominantly T-cell-driven)
  7. Novartis Animal Health / Elanco. ATOPICA (cyclosporine, modified) capsules for dogs, US package insert, 2003 (reference 1); and Olivry T, Mueller RS. Evidence-based veterinary dermatology: a systematic review of the pharmacotherapy of canine atopic dermatitis. Vet Dermatol. 2003;14(3):121-146 (reference 4). (how cyclosporine works, its slow onset of about 4 weeks, side effects, monitoring and which dogs are good candidates)
  8. Stability of Atopica capsules and ciclosporin pharmacokinetics in dogs after storage at -20 °C versus room temperature. Vet Dermatol. 2015. PMID 26178603. https://www.ncbi.nlm.nih.gov/pubmed/26178603 (8 healthy beagles; no difference in stability or blood levels after 28 days in the freezer; the study did not measure vomiting)
  9. Vetpharm, University of Zurich. Literature database entry on ciclosporin in canine atopic dermatitis. https://www.vetpharm.uzh.ch/lit/00000096/00009677.htm (giving the drug with food did not change the clinical response)
  10. University of Illinois College of Veterinary Medicine. Pharmacist's corner: common drug interactions. April 29, 2025. https://vetmed.illinois.edu/2025/04/29/pharmacists-corner-common-drug-interactions/ (ketoconazole raises cyclosporine blood levels and is sometimes used on purpose to lower the dose)
  11. Moyaert H, Van Brussel L, Borowski S, et al. A blinded, randomized clinical trial evaluating the efficacy and safety of lokivetmab compared to ciclosporin in client-owned dogs with atopic dermatitis. Vet Dermatol. 2017;28(6):593-e145. (274 dogs; at day 28 itch fell about 52% on lokivetmab and 44% on ciclosporin)
  12. Mueller RS, Jensen-Jarolim E, Roth-Walter F, et al. Allergen immunotherapy in people, dogs, cats and horses: differences, similarities and research needs. Allergy. 2018;73(10):1989-1999. (regulatory T cells, IL-10 and blocking IgG antibodies; much of the mechanism comes from human research)
  13. Keppel KE, et al. Quantitation of canine regulatory T cell populations, serum interleukin-10 and allergen-specific IgE concentrations in healthy control dogs and canine atopic dermatitis patients receiving allergen-specific immunotherapy. Vet Immunol Immunopathol. 2008. https://experts.illinois.edu/en/publications/quantitation-of-canine-regulatory-t-cell-populations-serum-interl/ (regulatory T cells and IL-10 rose over 12 months of immunotherapy)
  14. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5. PMID 26260508. (allergy testing is used to choose immunotherapy allergens, not to diagnose atopy; drug withdrawal before testing)
  15. Olivry T, DeBoer DJ, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the ICADA. BMC Vet Res. 2015;11:210 (reference 3); Mueller RS, Jensen-Jarolim E, Roth-Walter F, et al. Allergy. 2018;73(10):1989-1999 (reference 12); and Today's Veterinary Practice. Allergen immunotherapy for canine atopic dermatitis: an update. Jan/Feb 2022 (reference 18). (build-up and maintenance schedules, injection reactions, which dogs are candidates, and 6 to 12 months before judging)
  16. DeBoer DJ, Verbrugge M, Morris M. Clinical and immunological responses of dust mite sensitive, atopic dogs to treatment with sublingual immunotherapy (SLIT). Vet Dermatol. 2016;27(2):82-87, e23-24.
  17. Veterinary Information Network (VIN). Immunotherapy: subcutaneous vs. sublingual. https://vin.com/doc/?id=8896642 (about half of dogs who failed injections did well on drops; shots judged after at least 12 months and continued for years if they work)
  18. Nuttall TJ, Thoday KL, van den Broek AHM, Jackson HA, Sture GH, Halliwell REW. Retrospective survey of allergen immunotherapy in canine atopy. Vet Rec. 1998;143(5):139-142. Also: Today's Veterinary Practice. Allergen immunotherapy for canine atopic dermatitis: an update. Jan/Feb 2022. (a 9- to 12-month trial period)
  19. American College of Veterinary Dermatology. https://www.acvd.org (board certification of veterinary dermatologists in the US)
  20. Clinician's Brief. Pseudomonas otitis infection in cats and dogs. https://www.cliniciansbrief.com/article/pseudomonas-otitis-infection-cats-and-dogs (chronic otitis, end-stage ears and total ear canal ablation)
  21. Author's clinic pricing, Cypress, Texas, 2026, and Hearthstone Animal Clinic, Cypress dog allergies page. US online pharmacy prices, 2026: generic cyclosporine from about $30 a pack; Atopica 25 mg x 15 about $51. (estimates only; prices vary by clinic and city)

Chapter 18: Probiotics, gut health and the celebrity aisle

  1. Song H, Mun SH, Han DW, Kang JH, An JU, Hwang CY, Cho S. Probiotics ameliorate atopic dermatitis by modulating the dysbiosis of the gut microbiota in dogs. BMC Microbiol. 2025. doi:10.1186/s12866-025-03924-6. PMID 40264044. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12012994/ (cited for its gut-microbiome findings only)
  2. Thomsen M, Künstner A, Wohlers I, Olbrich M, Lenfers T, Osumi T, Shimazaki Y, Nishifuji K, Ibrahim SM, Watson A, Busch H, Hirose M. A comprehensive analysis of gut and skin microbiota in canine atopic dermatitis in Shiba Inu dogs. Microbiome. 2023;11:232. doi:10.1186/s40168-023-01671-2. https://pmc.ncbi.nlm.nih.gov/articles/PMC10590023/ (atopic dogs had fewer Fusobacteria and Megamonas; oclacitinib shifted the gut bacteria toward the healthy pattern)
  3. Sugita K, Shima A, Takahashi K, Ishihara G, Kawano K, Ohmori K. Pilot evaluation of a single oral fecal microbiota transplantation for canine atopic dermatitis. Sci Rep. 2023;13:8824. doi:10.1038/s41598-023-35565-y. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10230478/ (12 atopic dogs, open-label, no control group, 56 days)
  4. Marsella R. Evaluation of Lactobacillus rhamnosus strain GG for the prevention of atopic dermatitis in dogs. Am J Vet Res. 2009;70(6):735-740. PMID 19496662. https://pubmed.ncbi.nlm.nih.gov/19496662/
  5. Marsella R, Santoro D, Ahrens K. Early exposure to probiotics in a canine model of atopic dermatitis has long-term clinical and immunological effects. Vet Immunol Immunopathol. 2012;146(2):185-189. PMID 22436376. https://pubmed.ncbi.nlm.nih.gov/22436376/
  6. Pacheco RCF, Lins LF, de Brito LP, de Andrade Calaça PR, Porto ALF, Cavalcanti MTH. Probiotics as an adjunct in the treatment of canine atopic dermatitis: a systematic review and meta-analysis of in vivo studies in dogs. J Vet Med Sci. 2025;87(9):1068-1077. https://www.jstage.jst.go.jp/article/jvms/87/9/87_24-0471/_article (5 trials pooled; no significant effect on lesion scores or itch)
  7. Osumi T, et al. A double-blind, placebo-controlled evaluation of orally administered heat-killed Enterococcus faecalis FK-23 preparation in atopic dogs. Vet Dermatol. 2019;30(2):123-e36. doi:10.1111/vde.12725. PMID 30663154. (39 dogs; a small but measurable benefit on lesion scores as an add-on)
  8. Sordillo A, Heldrich J, Turcotte R, Sheth RU. An indole-rich postbiotic reduces itching in dogs: a randomized, double-blinded placebo-controlled study. Animals. 2025;15(14):2019. doi:10.3390/ani15142019. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12291873/ (30 mildly itchy dogs, 28 days, 20% less scratching; all four authors work for the ingredient maker)
  9. Pet Food Processing. Kingdom Supercultures postbiotic reduces itching in dogs. https://www.petfoodprocessing.net/articles/19464-kindgom-supercultures-postbiotic-reduces-itching-in-dogs ; and Petfood Industry. Study: novel postbiotic ingredient cuts dog itching by 20%. https://www.petfoodindustry.com/nutrition/research-notes/news/15750284/study-novel-postbiotic-ingredient-cuts-dog-itching-by-20
  10. Felten S, West, Martini, Favrot C, Unterer S, Suchodolski JS, Scharl, Renz, Fischer N, Rostaher A. Faecal microbiota transplantation reduces lesion severity and medication use in canine atopic dermatitis: a randomised, placebo-controlled, double-blinded clinical trial. Vet Dermatol. 2026. doi:10.1111/vde.70092. PMID 42286999. https://onlinelibrary.wiley.com/doi/full/10.1111/vde.70092 ; full text https://eprints.gla.ac.uk/388764/ (40 dogs completed 90 days; sustained responders 35% on FMT vs 5% on placebo; itch scores fell in both groups)
  11. Makrgeorgou A, Leonardi-Bee J, Bath-Hextall FJ, et al. Probiotics for treating eczema. Cochrane Database Syst Rev. 2018;11:CD006135. doi:10.1002/14651858.CD006135.pub3. https://cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006135.pub3/information (human data)
  12. PetSmart. Native Pet Dog Allergy Air-Dried Chews, Itch Relief and Immune Support, Chicken, 60 and 120 ct, product listing, viewed October 2026. https://www.petsmart.com/dog/vitamins-and-supplements/immune-system-and-allergy/native-pet-dog-allergy-air-dried-chews-itch-relief-and-immune-support-chicken-60-and-120-ct-85515.html (made with real chicken; formulated by veterinarians and vet nutritionists)
  13. National Animal Supplement Council. Regulation of Animal Health Supplements: A Historical Summary. https://www.nasc.cc/historical-summary/ (FDA CVM position, Federal Register, April 22, 1996; enforcement discretion)
  14. Nutraceuticals World. Pet nutrition: a legal rundown. April 2016. https://www.nutraceuticalsworld.com/issues/2016-04/view_columns/pet-nutrition-a-legal-rundown/
  15. US Food and Drug Administration. Guidance on dog and cat food products intended to diagnose, cure, mitigate, treat or prevent diseases (unapproved new animal drugs). https://fda.gov/media/83998/download
  16. US Food and Drug Administration. Warning letter to Merit Pet Products LLC, May 12, 2017. https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/merit-pet-products-llc-524285-05122017
  17. Petfood Industry. FDA issues warning letters to CBD and mushroom pet supplement makers. https://www.petfoodindustry.com/cbd-treats-for-dogs-and-cats/news/15746700/fda-issues-warning-letters-to-cbd-and-mushroom-pet-supplement-makers
  18. National Animal Supplement Council. Animal Health Supplement Act: July 2026 update. https://www.nasc.cc/news/animal-health-supplement-act-update-july-2026/ ; NutraIngredients. NASC pushes Animal Health Supplement Act to modernize oversight. June 8, 2026. https://nutraingredients.com/Article/2026/06/08/nasc-pushes-animal-health-supplement-act-to-modernize-oversight/ (bill drafted, introduction expected January 2027)
  19. National Animal Supplement Council. NASC and the NASC Quality Seal. https://www.nasc.cc/wp-content/uploads/2018/07/NASC-and-the-NASC-Quality-Seal-Final-for-Charlotte.pdf
  20. Veterinary Practice News. NASC launches Quality Seal program. https://www.veterinarypracticenews.com/?p=7060
  21. Weese JS. Microbiologic evaluation of commercial probiotics. J Am Vet Med Assoc. 2002;220(6):794-797. (organisms improperly identified in 8 of 23 veterinary products) Summary: https://skeptvet.com/2009/06/veterinary-probiotics/
  22. Weese JS, Arroyo L. Bacteriological evaluation of dog and cat diets that claim to contain probiotics. Can Vet J. 2003;44(3):212-215. https://pmc.ncbi.nlm.nih.gov/articles/PMC340078
  23. Weese JS, Martin H. Assessment of commercial probiotic bacterial contents and label accuracy. Can Vet J. 2011;52(1):43-46. https://pmc.ncbi.nlm.nih.gov/articles/PMC3003573/ ; summary: https://skeptvet.com/2011/04/veterinary-probiotics-sloppy-labeling-and-poor-quality-control/
  24. PR Newswire. Ultimate Pet Nutrition press release naming a TV actor as Chief Pet Advocate. February 7, 2025. https://www.prnewswire.com/news-releases/actor-rob-lowe-joins-ultimate-pet-nutrition-as-chief-pet-advocate-302371373.html
  25. Pet Insight. Ultimate Pet Nutrition names a Chief Pet Advocate. February 10, 2025. https://pet-insight.com/actor-rob-lowe-joins-ultimate-pet-nutrition-as-chief-pet-advocate/ ; Petfood Industry. Ultimate Pet Nutrition names a chief pet advocate. https://www.petfoodindustry.com/pet-food-marketing-and-branding/news/15737294/ultimate-pet-nutrition-names-rob-lowe-as-chief-pet-advocate
  26. Pet Insight. Ultimate Pet Nutrition Nutra Complete and Nutra Thrive launch in 650 Pet Supplies Plus stores. June 11, 2025. https://pet-insight.com/ultimate-pet-nutrition-nutra-complete-and-nutra-thrive-launch-in-650-pet-supplies-plus-stores/ ; Pet Food Processing. https://www.petfoodprocessing.net/articles/19367-ultimate-pet-nutrition-expands-into-pet-supplies-plus-stores (Nutra Thrive described as more than 40 nutrients, including probiotics and digestive enzymes)
  27. Chewy. Ultimate Pet Nutrition Nutra Thrive Multivitamin 40-in-1 Powder Supplement for Dogs, product listing, viewed October 2026. https://www.chewy.com/ultimate-pet-nutrition-nutra-thrive/dp/573446 ; also https://shop.wihumane.org/products/ultimate-pet-nutrition-nutra-thrive-40-in-1-canine-nutritional-supplement-topper-for-dogs
  28. Walmart. Freeze-dried food (Sensitivity Select), 16 oz, product listing, viewed October 2026. https://www.walmart.com/ip/seort/15080550577
  29. Canine Journal. Freeze-dried food line reviews. https://www.caninejournal.com/dr-marty-dog-food-reviews/ (third-party summary; "less itching" is the review site's wording)
  30. PetSmart. Native Pet Allergy and Immune Chews, product listing, viewed October 2026. https://www.petsmart.com/dog/vitamins-and-supplements/immune-system-and-allergy/native-pet-allergy-and-immune-chews-allergy-and-itch-relief-supplement-for-dogs-5357040.html ; Chewy. Native Pet allergy bundle with vet-formulated probiotic powder. https://www.chewy.com/native-pet-allergy-air-dried/dp/894326
  31. The Forever Dog. HarperCollins; 2021. https://www.librarything.com/work/26903283 (bestselling book on canine diet and longevity)
  32. SkeptVet. Book review: The Forever Dog. https://skeptvet.com/?p=4089 (opinion)
  33. PetSmart. PetLab Co. Dog Probiotic Supplement Chews, product listing, viewed October 2026. https://www.petsmart.com/dog/vitamins-and-supplements/probiotic-and-digestive/petlab-co-dog-probiotic-supplement-chews-support-gut-health-multiple-dog-sizes-pork-flavor-30ct-5371756.html ; also Canine Journal, https://www.caninejournal.com/petlab-co-reviews/ ("84% of PetLab Co. subscribers have seen benefits within 90 days")
  34. Chewy. PetLab Co. Allergy and Immune Probiotic Chew, 30 count, product listing, viewed October 2026. https://www.chewy.com/petlab-co-allergy-immune-probiotic/dp/1040366 (regular price about $35.95; first-order Autoship discount)
  35. Author's search of public enforcement records (FTC actions, National Advertising Division cases, FDA warning letters and class actions) for the brands named in this chapter, October 2026. (none found; absence from search results is not proof that none exists)
  36. BBB National Programs. Certain advertising claims for Doggie Dailies dietary supplement permanently discontinued following NAD inquiry. https://bbbprograms.org/media-center/press-releases-details/certain-advertising-claims-for-doggie-dailies-dietary-supplement-permanently-discontinued-following-national-advertising-division-inquiry
  37. Manatt, Phelps & Phillips. NAD brings dog supplement claims to heel. https://manatt.com/insights/newsletters/advertising-law/nad-brings-dog-supplement-claims-to-heel
  38. Mueller RS, Fieseler KV, Fettman MJ, et al. Effect of omega-3 fatty acids on canine atopic dermatitis. J Small Anim Pract. 2004;45(6):293-297. PMID 15206474. https://pubmed.ncbi.nlm.nih.gov/15206474/ (29 atopic dogs, 10 weeks, fatty acids vs placebo)
  39. Sævik BK, Bergvall K, Holm BR, et al. A randomized, controlled study to evaluate the steroid sparing effect of essential fatty acid supplementation in the treatment of canine atopic dermatitis. Vet Dermatol. 2004;15(3):137-145. (60 dogs, 12 weeks; itch and lesion scores lower on fatty acids by the end, after a lag)
  40. Olivry T, DeBoer DJ, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4537558/
  41. Author's clinic pricing, Cypress, Texas, 2026, and the retail listings cited in this chapter. The "stack of three" row is simple arithmetic on an assumed $30 to $50 per product per month, not a quoted price. Estimates only.

Chapter 19: Your marketing BS detector

  1. Olivry T, DeBoer DJ, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6 (atopic dermatitis is lifelong and managed with combined, individualized treatment)
  2. PetSmart. Native Pet Dog Allergy Air-Dried Chews, Itch Relief & Immune Support, product listing, viewed October 2026. https://www.petsmart.com/dog/vitamins-and-supplements/immune-system-and-allergy/native-pet-dog-allergy-air-dried-chews-itch-relief-and-immune-support-chicken-60-and-120-ct-85515.html (an example of "formulated by veterinarians" marketing; no published controlled trial of the finished product)
  3. PetSmart. PetLab Co. Dog Probiotic Supplement Chews, product listing, viewed October 2026. https://www.petsmart.com/dog/vitamins-and-supplements/probiotic-and-digestive/petlab-co-dog-probiotic-supplement-chews-support-gut-health-multiple-dog-sizes-pork-flavor-30ct-5371756.html ("84% of PetLab Co. subscribers have seen benefits within 90 days"; a customer survey, not a controlled trial)
  4. US Federal Trade Commission. Bringing Dark Patterns to Light. Staff report, September 2022. (false scarcity claims, countdown timers and hard-to-cancel subscriptions as manipulative design)
  5. US Food and Drug Administration, Center for Veterinary Medicine. Products intended to diagnose, cure, mitigate, treat or prevent disease in animals are drugs under the FD&C Act; marketed without approval they are unapproved new animal drugs. https://fda.gov/media/83998/download (Chapter 18 covers supplement regulation in full)
  6. US Federal Trade Commission. Guides Concerning the Use of Endorsements and Testimonials in Advertising, 16 CFR Part 255 (revised 2023). (testimonials are expected to reflect typical results)
  7. Dechra Veterinary Products. Malacetic Otic ear cleanser (acetic acid and boric acid), product label. (an example of acetic acid used in veterinary ear cleaners)
  8. Luu LA, Flowers RH, Kellams AL, et al. Apple cider vinegar soaks [0.5%] as a treatment for atopic dermatitis do not improve skin barrier integrity. Pediatr Dermatol. 2019;36(5):634-639. Summary: https://nationaleczema.org/acv-skin-barrier-ineffective/ (human study of 22 people; no barrier improvement; mild irritation in 72.7%)
  9. dvm360. Debunking the coconut oil fad in veterinary dermatology. https://www.dvm360.com/view/debunking-the-coconut-oil-fad-in-veterinary-dermatology (no known placebo-controlled trials of coconut oil in dogs)
  10. US Department of Agriculture, FoodData Central. Oil, coconut. (about 120 kcal per tablespoon, 13.6 g)
  11. WSAVA Global Nutrition Committee calorie guidance; standard resting energy formula 70 x (body weight in kg)^0.75. (a 55 lb, 25 kg neutered adult dog needs roughly 940 to 1,250 kcal a day; individual needs vary widely)
  12. Lem KY, Fosgate GT, Norby B, Steiner JM. Associations between dietary factors and pancreatitis in dogs. J Am Vet Med Assoc. 2008;233(9):1425-1431. (getting into the trash, table scraps and unusual foods were linked with pancreatitis)
  13. Campora L, Miragliotta V, Ricci E, et al. Cannabinoid receptor type 1 and 2 expression in the skin of healthy dogs and dogs with atopic dermatitis. Am J Vet Res. 2012;73(7):988-995.
  14. Loewinger M, Wakshlag JJ, Bowden D, Peters-Kennedy J, Rosenberg A. The effect of a mixed cannabidiol and cannabidiolic acid based oil on client-owned dogs with atopic dermatitis. Vet Dermatol. 2022;33(4):329-e77. doi:10.1111/vde.13077. PMID 35644533. https://pubmed.ncbi.nlm.nih.gov/35644533/ (32 dogs, 4 weeks, as an add-on; owner-scored itch fell vs placebo, skin lesions did not)
  15. Wakshlag JJ, Cital S, Eaton SJ, Prussin R, Hudalla C. Cannabinoid, terpene, and heavy metal analysis of 29 over-the-counter commercial veterinary hemp supplements. Vet Med (Auckl). 2020;11:45-55. Summary: https://norml.org/news/2020/05/07/study-cbd-products-marketed-toward-pets-suffer-from-quality-control-issues/ (only 10 of 27 within 10% of the labeled cannabinoid content; heavy metals in 4 of 29)
  16. Leafreport pet CBD product testing (Canalysis Laboratories), May 2021, as reported in NutraIngredients-USA. Industry watchdog: over half of CBD products for pets make incorrect label claims. May 25, 2021. https://www.nutraingredients-usa.com/Article/2021/05/25/Industry-watchdog-Over-half-of-CBD-products-for-pets-make-incorrect-label-claims (24 of 55 products contained the advertised amount; not peer reviewed)
  17. Bradley S, Young S, Bakke AM, et al. Long-term daily feeding of cannabidiol is well-tolerated by healthy dogs. Front Vet Sci. 2022;9:977457. doi:10.3389/fvets.2022.977457. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9533147/ (20 dogs on CBD for 6 months; a temporary rise in the liver enzyme ALP in just over half)
  18. US Food and Drug Administration. Warning letters posted April 7, 2025, including House of Alchemy LLC dba CBD Dog Health and Bailey's Wellness LLC dba Bailey's CBD. https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/baileys-wellness-llc-dba-baileys-cbd-701066-04072025 ; coverage: Veterinary Practice News, FDA issues warning letters to pet CBD companies. https://www.veterinarypracticenews.com/fda-warning-letters-cbd-companies/
  19. Congressional Research Service. Change to Federal Definition of Hemp and Implications for Federal Enforcement. IN12620, December 2025. https://www.congress.gov/crs_external_products/IN/PDF/IN12620/IN12620.2.pdf (total THC limit of 0.4 mg per container for final products, effective November 12, 2026)
  20. Khan SA, McLean MK, Slater MR. Concentrated tea tree oil toxicosis in dogs and cats: 443 cases (2002-2012). J Am Vet Med Assoc. 2014;244(1):95-99. Summary: https://www.vetstreet.com/our-pet-experts/what-you-should-know-about-tea-tree-oil-toxicity-in-dogs-and-cats (ASPCA Animal Poison Control Center records, 337 dogs and 106 cats)
  21. Genovese AG, McLean MK, Khan SA. Adverse reactions from essential oil-containing natural flea products exempted from Environmental Protection Agency regulations in dogs and cats. J Vet Emerg Crit Care. 2012;22(4):470-475. PMID 22805458. (serious reactions possible even when used as directed; see also Chapter 6 references)
  22. van Bree FPJ, Bokken GCAM, Mineur R, et al. Zoonotic bacteria and parasites found in raw meat-based diets for cats and dogs. Vet Rec. 2018;182(2):50. (35 commercial frozen raw diets: Listeria monocytogenes in 54%, Salmonella in 20%; see also Chapter 5 references)
  23. American Veterinary Medical Association. Policy: Raw or undercooked animal-source protein in cat and dog diets. https://www.avma.org/resources-tools/avma-policies
  24. Thomsen M, Künstner A, Wohlers I, et al. A comprehensive analysis of gut and skin microbiota in canine atopic dermatitis in Shiba Inu dogs. Microbiome. 2023;11:232. doi:10.1186/s40168-023-01671-2. https://pmc.ncbi.nlm.nih.gov/articles/PMC10590023/ (oclacitinib shifted the gut bacteria toward the healthy pattern)
  25. Klein AV, Kiat H. Detox diets for toxin elimination and weight management: a critical review of the evidence. J Hum Nutr Diet. 2015;28(6):675-686. (human research)
  26. Investigation of the clinical efficacy of quercetin in feline atopic dermatitis syndrome. Acta Fytotechnica et Zootechnica. https://afz.fapz.uniag.sk/journal/article/view/638 (no published controlled trial of quercetin in dogs with atopic dermatitis was found as of October 2026; this small cat study is the closest)
  27. Olivry T, DeBoer DJ, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the ICADA. BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6. See also Veterinary Evidence knowledge summary. Managing atopic dermatitis in dogs: are antihistamines as effective as glucocorticoids? doi:10.18849/ve.v5i4.335 (weak, conflicting evidence for antihistamines)
  28. Dogster. Benefits of colostrum for dogs (vet answer). https://dogster.com/ask-the-vet/benefits-of-colostrum-for-dogs-vet-answer (no systematic studies of colostrum's immune effects in dogs have been reported; no controlled trial in dogs with allergic skin disease was found as of October 2026)
  29. Mueller RS, Olivry T, Prélaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Vet Res. 2016;12:9. doi:10.1186/s12917-016-0633-8 (beef and dairy among the most commonly reported, 1985 to 2015 data)
  30. Standard dilution arithmetic: a 30C remedy is diluted 1:100 thirty times, a total dilution of 1 in 10^60. A mole of any substance holds about 6 x 10^23 molecules (Avogadro's number), so past roughly 12C the chance that even one molecule of the original substance remains in a dose is vanishingly small.
  31. Mathie RT, Clausen J. Veterinary homeopathy: systematic review of medical conditions studied by randomised placebo-controlled trials. Vet Rec. 2014;175(15):373-381. https://vetsrev.nottingham.ac.uk/bibliography/mathie_veterinary_2014.html (18 trials; only 2 reliable trials free of vested interest, with mixed findings)
  32. Hill PB, Hoare J, Lau-Gillard P, Rybníček J, Mathie RT. Pilot study of the effect of individualised homeopathy on the pruritus associated with atopic dermatitis in dogs. Vet Rec. 2009;164(12):364-370. https://bristol.ac.uk/news/2009/6274.html (20 atopic dogs; owners of 15 saw no improvement)
  33. Coyner K, Schick A. Hair and saliva analysis fails to accurately identify atopic dogs or differentiate real and fake samples. Vet Dermatol. 2019;30(1). doi:10.1111/vde.12716. PMID 30680834. (every sample, including synthetic fur and sterile saline, tested positive; see also Chapter 10 references)
  34. US Food and Drug Administration. Hypoallergenic cosmetics. (no federal standard or definition governs the term "hypoallergenic")
  35. Barnett AG, van der Pols JC, Dobson AJ. Regression to the mean: what it is and how to deal with it. Int J Epidemiol. 2005;34(1):215-220. doi:10.1093/ije/dyh299
  36. Conzemius MG, Evans RB. Caregiver placebo effect for dogs with lameness from osteoarthritis. J Am Vet Med Assoc. 2012;241(10):1314-1319. PMID 23113523. https://pubmed.ncbi.nlm.nih.gov/23113523/ (58 dogs; owners saw improvement on placebo 39.7% of the time while force-plate measurements didn't change)
  37. Author's clinic pricing, Cypress, Texas, 2026, and Hearthstone Animal Clinic, Cypress dog allergies page (flea prevention, fish oil and medicated shampoo). Estimates only.
  38. Chewy. PetLab Co. Allergy & Immune Probiotic Chew, about $35.95 regular price, https://www.chewy.com/petlab-co-allergy-immune-probiotic/dp/1040366 ; and PetSmart. Native Pet allergy chews, about $24.99 (60 ct) to $39.99 (120 ct). Listings viewed October 2026.
  39. Estimated range for pet CBD oils at typical label doses for a 55 lb dog, based on US retail listings, 2026. Estimate only.

Chapter 20: Life with an itchy dog (it gets better)

  1. Hensel P, Santoro D, Favrot C, Hill P, Griffin C. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Vet Res. 2015;11:196. doi:10.1186/s12917-015-0515-5. PMID 26260508. (atopic dermatitis is a genetically predisposed, lifelong disease that usually starts between 6 months and 3 years of age)
  2. Olivry T, DeBoer DJ, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Vet Res. 2015;11:210. doi:10.1186/s12917-015-0514-6 (separate approaches for acute flares and chronic disease; avoiding flare factors; proactive long-term management)
  3. Lourenço AM, Schmidt V, São Braz B, Nóbrega D, Nunes T, Duarte-Correia JH, Matias D, Maruhashi E, Rème CA, Nuttall T. Efficacy of proactive long-term maintenance therapy of canine atopic dermatitis with 0.0584% hydrocortisone aceponate spray: a double-blind placebo controlled pilot study. Vet Dermatol. 2016;27(2):88-92, e25. (dogs on twice-weekly spray went much longer before their next flare than dogs on placebo, with no adverse events)
  4. Linek M, Favrot C. Impact of canine atopic dermatitis on the health-related quality of life of affected dogs and quality of life of their owners. Vet Dermatol. 2010;21(5):456-462. doi:10.1111/j.1365-3164.2010.00899.x (questionnaire of 98 owners; nearly half reported an effect on their own quality of life)
  5. Spitznagel MB, Jacobson DM, Cox MD, Carlson MD. Caregiver burden in owners of a sick companion animal: a cross-sectional observational study. Vet Rec. 2017;181(12):321. doi:10.1136/vr.104295 (owners of chronically or terminally ill pets had higher caregiver burden, stress, depression and anxiety symptoms than owners of healthy pets)
  6. MSD Animal Health. Global canine itch survey of 1,413 veterinarians in 11 countries and 1,710 dog owners in 8 countries, fielded February to April 2025, published June 2026. https://www.msd-animal-health.com/news-and-insights/featured-stories/itchsurvey/ ; US fact sheet: https://www.msd-animal-health.com/wp-content/uploads/sites/174/2026/06/MAH_itch_FactSheet_US_FINAL.pdf (industry-sponsored; 34% of US owners reported a notable negative effect on their own quality of life)
  7. Elanco Animal Health. America's Itchy Dogs report, 2025. https://assets.elanco.com/0cec44ed-3eaa-0009-2029-666567e7e4de/33474a48-bac3-4fc4-b7fc-3589b88560fb/ElancoItchyDogsReportFINAL.pdf (industry-sponsored)
  8. Shaw SC, Wood JLN, Freeman J, Littlewood JD, Hannant D. Estimation of heritability of atopic dermatitis in Labrador and Golden Retrievers. Am J Vet Res. 2004;65(7):1014-1020. PMID 15281664. (heritability estimate 0.47, from 429 related dogs)
  9. Reeder C. Dermatologic markers of internal disease in dogs and cats. Today's Veterinary Practice. https://todaysveterinarypractice.com/dermatology/dermatology-details-dermatologic-markers-of-internal-disease-in-dogs-cats/ (a dog with hormone disease generally isn't itchy unless the skin is infected)
  10. Fontaine J, Bovens C, Bettenay S, Mueller RS. Canine cutaneous epitheliotropic T-cell lymphoma: a review. Vet Comp Oncol. 2009;7(1):1-14. PMID 19222826. (mostly older dogs; redness, scaling, plaques and itch; early lesions can look like allergic or inflammatory skin disease)

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