Updates on the Pathogenesis of Canine and Feline Atopic Dermatitis: Part 1, History, Breed Prevalence, Genetics, Allergens, and the Environment.

Canine atopic dermatitis (cAD) and feline atopic skin syndrome are inflammatory and pruritic skin diseases with both environmental and genetic factors. Genetic factors may include barrier defects and a predisposition to mount T helper 2 lymphocyte immune response when allergens are encountered. These diseases have repeatable patterns of skin and ear inflammation and commonly lead to Staphylococcal and Malassezia skin and ear infections. Early life environmental factors and an indoor lifestyle may increase the risk of cAD. The most ubiquitous environmental allergen is house dust mite with pollens, molds, foods, and Malassezia yeast potentially playing a role in affected individuals.