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

Abstract

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. Th-2 cytokine products IL-4, IL-13, and IL-31 are increased in the acute allergic inflammatory response. Altered response in T-helper 1, T-helper 17, and T-regulatory cells play a role in both acute and chronic allergic inflammation.