Atopy (Atopic Dermatitis) in Dogs

Atopy, also known as atopic dermatitis, is an inherited condition in which the affected dog develops a hypersensitivity to environmental allergens, such as pollens, molds, and/or certain insects like house dust mites. Atopic dermatitis is one of the most common skin diseases in the dog and second most common hypersensitivity in the cat. Commonly affected breeds include terriers, golden retrievers, Labrador retrievers, Lhasa apsos, and Shih tzu.

Clinical signs most often develop between six months and three years of age, are often distinctly seasonal in the beginning, and commonly involve the ears, distal  extremities, and face. Atopy often cannot be distinguished from food allergies without a history of seasonal occurances. Recurrent bacterial skin infections, Malassezia (yeast) skin inflammation, and ear inflammation are often present in allergic dogs.

Common clinical signs and symptoms include:

• Pruritus (itching, face rubbing, paw licking), with or without visible skin lesions (redness)
• Alopecia (hair loss)
• Lichenification (leathery development and thickening of the skin)
• Hyper-pigmentation (darkening of the skin)
• Other allergies that may be co-existing: flea allergy dermatitis and adverse food reaction
• Symptoms typically begin during young adulthood, between 1 and 3 years of age

Treatment:

• Essential Fatty Acids and antihistamines may be recommended to manage the mind symptoms of atopy.
• More severe symptoms may require oral corticosteroids or cyclosporine for effective management.
• Chronic symptoms can be effectively managed with allergen-specific immunotherapy (allergy shot).  Hyposensitization (also called desensitization or allergy vaccination) involves subcutaneous injection of relevant allergens at intervals and in increasing concentrations (induction period), until the target maintenance dose is reached. 
• Any secondary bacterial infection requires antibiotic therapy.
• For those dogs with a particular predisposition to bacterial and yeast infections, frequent use of shampoos containing antibacterial and antifungal agents is often beneficial.  
• There is no single uniformly effective therapeutic agent or management approach for canine atopy.  The successful remedy is usually a combination of topical treatments, systemic therapeutics and environmental changes.