A type 1 hypersensitivity reaction to inhaled or cutaneously absorbed environmental antigens(allergens) in genetically predisposed indiviuals.  Common in dogs, with age of onset ranging from 3 months to 7 years.  However, in most atopic dogs, symptoms first appear between 1 and 3 years of age.

There are at least five common types of allergy in the dog:

  • Flea

  • Inhalant

  • Food

  • Contact

  • Bacterial Hypersensitivity

Most dogs with allergies develop skin symptoms, especially itching, although the allergy may also affect the respiratory or digestive system, or the eyes.


The signs associated with atopic dermatitis consist of constant itching, scratching, rubbing, and licking, especially around the face, paws, and underarms.


Serologic allergy testing may be performed, but it does not always have reliable results. The quality of this kind of testing often depends on the laboratory which analyzes the results.

Alternatively, a long acting low dose of steriod injection can be given to the dog.  If all symptoms reduces, it would most likely be due to allergies.


Medicines such as corticosteroids and antihistamines can also be given to control or reduce itching. Cyclosporine and Apoquel are effective in controlling itching associated with long-term skin allergies, while sprays or anti-allergen shampoo can be used over large body surfaces to control itching with minimal side effects.