Glossary

Atopic dermatitis

An inherited tendency to develop itchy skin and ear disease from allergens in the environment such as pollen, dust mites and molds.

Also called: atopy, canine atopy, environmental allergies, allergic skin disease, seasonal allergies in dogs

Atopic dermatitis, often called atopy, is a long-term allergic skin disease in which the immune system overreacts to harmless substances such as pollen, house dust mites and molds. Symptoms usually begin in young dogs, often before age three, and they may be seasonal or year-round.

The typical picture is an itchy dog that licks its paws, rubs its face, scratches its armpits and belly, and gets repeat ear infections or hot spots. Skin becomes red, then darker and thickened. Breeds such as the West Highland White Terrier and Labrador Retriever are often affected.

Other causes of itch, such as fleas, mites and food allergy, must be ruled out first. Atopy is usually managed, not cured, with a plan from a veterinarian or a veterinary dermatologist.

Last reviewed November 8, 2026

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Related terms

Food allergy An immune reaction to a protein in the diet that usually causes itchy skin and ear problems, and sometimes digestive upset. Ear infection Inflammation of the outer ear canal, often with yeast or bacteria, causing head shaking, scratching, odor and pain. Hot spot A fast-appearing, red, wet and painful patch of skin that a dog creates by licking or scratching, usually because of an underlying irritation. Fleas Tiny blood-feeding insects that cause itching, can trigger allergic skin disease and carry tapeworm, and infest the home as well as the dog.