Canine Allergic Dermatitis and Atopy: NAVLE Study Guide

Allergic skin disease is the most common reason dogs visit veterinarians, and it shows up reliably on the NAVLE. Three types dominate the question pool: canine atopic dermatitis (CAD), flea allergy dermatitis (FAD), and adverse food reaction. The exam almost always tests your ability to distinguish them by distribution, signalment, and seasonality – and then pick the right treatment.

Canine Atopic Dermatitis (CAD)

CAD is a Type I IgE-mediated hypersensitivity to environmental allergens – dust mites, pollens, mold spores. Allergen exposure triggers mast cell degranulation, histamine release, and the characteristic inflammatory cascade that keeps atopic dogs itchy year-round (or seasonally if pollens dominate).

Breed predisposition is a major NAVLE signal. West Highland White Terrier has one of the highest relative risks. Others to know: Golden Retriever, Labrador Retriever, Boxer, Bulldog, Shar Pei, and Cocker Spaniel. Age of onset is typically 1–3 years. If a dog develops pruritus before age 1 or after age 7, think harder about alternatives.