Allergic dermatitis in dogs refers to inflammatory skin conditions caused by any type of allergy, and may be temporary or life-long. Aside from the common symptoms of the allergic condition itself, the pet will frequently suffer from more than one allergic condition at once. This, along with the propensity for them to develop secondary infections as well, can make the diagnosis and treatment of allergic dermatitis very challenging.

The most common classes of allergic dermatitis seen in dogs are flea bite allergy, food allergy, and atopy. Atopy, or atopic dermatitis, is a hypersensitivity reaction caused by inhaled allergens, or absorption of allergens through the skin. Some other causes of allergic dermatitis in dogs may arise from urticaria and angioedema, contact hypersensitivity, hypersensitivity to the bites of ticks, mosquitos, or other insects, ear mites, or intestinal parasites. Bacterial infections such as staph infections, or Malassezia overgrowth may also cause symptoms.

The clinical signs of most allergic hypersensitivity reactions display similar symptoms, including pruritis (itching), erythema (redness), hair loss, raised red pimple-like skin lesions with a scaly appearance, hyperpigmentation or discoloration of the skin, and lichenification (leather-like thickening from constant scratching, licking, or rubbing of the skin).

Some of the factors that may be responsible for the development of allergic dermatitis include the predisposition of certain breeds, genetic factors, and environmental or seasonal allergy conditions. Diagnosis can be complicated by the presence of secondary or underlying conditions, so other diseases and characteristic symptoms must first be excluded. Allergic dermatitis is generally diagnosed by collecting a thorough medical history, physical examination, skin scrapings, skin cytology, and bloodwork. Additional tests such as allergy blood tests, intradermal allergy testing, and dietary trials may also be necessary.

Treatment depends on the diagnosis of the disease, your individual pet, and your veterinarian. Pets with allergic dermatitis may be treated with special shampoos, topical medications, antibiotics, antihistamines, steroids, special diet or immunotherapy. Food allergies may be treated by experimenting with hypoallergenic diets or the exclusion of ingredients known to cause the symptoms. Treatments targeted at preventing insect bites are also helpful. Discuss treatment details with your veterinarian when your pet is diagnosed with this condition.