Dermatitis in Dogs Diagnosis & Treatment

Atopic dermatitis in dogs (allergic dermatitis, canine atopy) is a hypersensitivity or over-reaction to a variety of commonplace and otherwise harmless substances in the environment.

These allergens include plant pollens, house dust mites, or mold spores. Most allergic dogs begin to show signs between one and three years of age. Due to the hereditary nature of the disease, several breeds of dogs appear predisposed to allergies. These dog breeds include Golden Retrievers, Labrador Retrievers, West Highland White Terriers and other terriers, and Bulldogs. However any dog, including mixed breed dogs, can have atopic dermatitis.

Signs

Atopic dogs will scratch, chew, lick their paws, rub their face, or have recurrent ear infections. This itchy behavior, or pruritus, can cause hair loss and reddening and thickening of the skin. In some dogs, other causes can work with a dog’s allergies to cause itching. For example, parasites such as fleas or infection from bacteria or yeast can all worsen the level of itching from allergies. Therefore, it is important to treat any other health problems that could cause itching to manage your pet’s allergies.

Diagnosis

Allergy tests are used to identify what a pet is allergic to in the environment. There are two types of allergy tests, the intradermal allergy test and blood testing for allergies (serologic allergy testing). In an intradermal allergy test, the fur is clipped on one side of the chest and very small amounts of common allergens are injected into the skin. In a blood allergy test, a blood sample is obtained and sent to a laboratory for testing.

Treatment

If a dog is diagnosed with atopic dermatitis, there are three methods of therapy.

• Avoiding allergens: It is usually not possible to remove all allergens from a pet’s environment because even a small amount of an allergen can trigger a dog’s allergies. However, bathing can help remove allergens from the skin. A hypoallergenic cream rinse or spray can re-moisturize the skin after bathing.
• Medications: A variety of anti-allergy drugs are available. These drugs include antihistamines, steroids (cortisone), cyclosporine and newer drugs such as oclactinib. Some dogs develop side-effects from taking certain anti-itch medications, such as steroids. Different anti-allergy medications may need to be tried because not every medication works in all pets.
• Allergen specific immunotherapy: Immunotherapy involves giving a series of diluted allergens based on what your dog is allergic to. Allergen-specific immunotherapy makes dogs less sensitive to their allergens and 60-80% of patients improve on immunotherapy. However, improvement on immunotherapy takes time and it is important try the immunotherapy for several months so it can take effect. When helpful, immunotherapy is usually continued life-long but can be administered less frequently over time.

Dr. Alex Hare