Atopic Dermatitis in Dogs

Alison Laurie-Chalmers, Senior Consultant, Crown Vets Inverness

Atopic dermatitis is an allergic skin disease of dogs which is caused by immunological hypersensitivity to common substances in the environment. It is an inflammatory, chronic skin disease and is one of the most common skin diseases in dogs and cats. An inappropriate immune response is produced to normal substances, allergens and the resulting skin inflammation causes a chronic skin disease. These allergic reactions can be brought on by normally harmless substances like mould spores, house dust mites, food storage mites and other environmental allergens such as grass, weed and tree pollens. It is common for dogs to be allergic to a variety of different things i.e. food as well as multiple allergens in the environment.

Unfortunately, certain breeds of dog such as West Highland White Terriers, Labradors, Chinese SharPeis and Springer Spaniels are more prone to developing the disease. Dogs can show first signs of the disease between 3 months and 6 years of age. However, atopic dermatitis can be so mild during their first year that it does not become clinically apparent before their third year of age. Patients with this disease do have it for the duration of their lives and the skin symptoms must be managed and controlled in the long term.

Symptoms of atopic dermatitis progressively worsen with time, and often become more apparent during particular seasons such as spring and summer. Atopy usually presents with intense itching, scratching, rubbing and licking and very commonly affects the skin around the eyes, muzzle, ears, lower limbs, paws, abdomen, armpits and groin. Saliva staining on the coat is commonly seen in these animals noted as a red-brown staining of hair. The skin itself may also change colour. Instead of being pink, a black mottling (hyperpigmentation) will slowly develop, especially if the skin has already been inflammed. Secondary bacterial and yeast infections are common, causing ear infections and eye problems such as conjunctivitis.

Finding out exactly what your dog is allergic to can be very challenging. Your vet will want a complete medical history to determine the underlying cause of the skin allergies, including a full physical examination of your dog to rule out other causes of intense itching, for example fleas. Blood tests involving serology allergy testing may be performed but do not always have reliable results. Intradermal allergy testing, where small amounts of test allergens are injected under the skin and any reactive weal response is measured, may also be used to identify the cause of your pet's intense allergic reaction.

Treatments for atopic dermatitis aim to reduce the over-active immune system and improve the overall skin barrier to prevent further penetration of the allergens. Treatment for atopy often includes a special diet and medications to relieve the itch and skin supplements. Allergen avoidance is useful, if the actual allergens are known.

Without any treatment, atopy can be distressing as constant itching and sore skin can make an animal very miserable. However, with proper treatment, pets with atopy can live a comfortable, happy life. Treatments do not cure the condition but aim to control the symptoms and so improve the patient’s general well-being and comfort. Flare ups can be common and they can be resolved by visiting your vet regularly for the correct treatment. In some cases, it may be advised that your pet is referred to a Veterinary Dermatologist.