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.

Updates on the Pathogenesis of Canine Atopic Dermatitis and Feline Atopic Skin Syndrome: Part 2, the Skin Barrier, the Microbiome, and Immune System Dysfunction.

Alterations in the lipid layer and intercellular corneocyte connections can lead to increased allergen penetration through the skin surface. A normal cutaneous microbiome keeps the opportunistic pathogen Staphylococcus pseudintermedius levels low, but allergic inflammation leads to decreased diversity and increase in S pseudintermedius. Keratinocytes sound the initial allergen alarm via cytokine signaling and promote T-helper 2 (Th-2) inflammation.

Alfaxalone provides reliable sedation for intradermal allergen testing in dogs and does not significantly affect results when compared to dexmedetomidine.

Background: Dexmedetomidine (Dexmedetomidine hydrochloride-Dexdomitor; Zoetis) is the preferred sedative used for canine intradermal allergen testing (IDT) in the United States. Alfaxalone (Alfaxan Multidose; Jurox Animal Health) is a neuroactive steroid, and its effect on sedation and allergen reactivity scores is unknown.

Hypothesis/objectives: We hypothesised that alfaxalone would produce an adequate level of sedation with fewer cardiovascular adverse effects and would not affect allergen reactivity scores or histamine wheal size compared to dexmedetomidine.

Comparison of intradermal and percutaneous testing to histamine, saline and nine allergens in healthy adult cats.

Background: Intradermal testing (IDT) in cats has potential limitations; this has led to an interest in novel testing methods. A pilot study demonstrated that healthy cats produced reliable percutaneous glycerinated (PG) histamine wheals, whereas percutaneously applied glycerosaline did not lead to wheal formation.

Hypothesis/objective: The purpose of this study was to determine if percutaneously applied aqueous and glycerinated allergens would lead to irritant reactions in healthy cats.