Allergic Skin Disease

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When a dog is ‘allergic’ to something his body is reacting to certain molecules called ‘allergens’.

Allergens come from:

• trees, grass, weed pollens
• fabrics such as wool or nylon
• rubber and plastic material
• house dust and dust mites
• foods such as meats, grains, milk or colourings
• flea bites

When these allergens come into contact with your dog’s body, it overreacts causing itchy skin.

Symptoms

• chew his feet
• rub his face
• self mutilate
• have recurrent ear infections
• scratch and have hair loss

Diagnosing

• Physical examination
• Skin scrapes, hair plucks, tape strips, swabs; looking for evidence of other causes of skin disease such as parasites + bacteria
• Allergy testing (intradermal or blood testing)
• Food trials

Treatment

• Avoidance; Although, it can be impossible to eliminate all offending agents, some can be reduced without too much effort. For example, vacuum regularly, wash bedding in very hot water, plastic cover on dog’s bed, avoid dusty pet foods, use regular flea treatments.
• Antihistamines; Normally in a tablet form they help to reduce the amount and effect of histamine release which causes the itchy skin.
• Immunotherapy or hyposensitization; Once the allergens to which the dog is allergic to have been identified (usually by blood testing) a specially prepared vaccination containing the altered antigens are injected into the dog. Generally a series of weekly or monthly vaccines are given to try to de-sensitise the dog.
• Fatty acids; These, reduce the effects of histamine and other chemicals released in response to allergies. Most pets need to be taking them for several weeks before a significant improvement is seen.
• Cyclosporine; Has the brand name ‘Atopica’ and comes in tablet form. It works by suppressing the immune system. It may take up to 3-4 weeks to take effect, but can be used for a short period of time for seasonal allergies or long-term for year round problems. They are quite costly, especially for large breeds and for long periods of time.
• Corticosteroids; These come in tablet or injectable form and are less expensive. Oral dosing is easier to customize to individual dosing and usually starts with twice daily dosing and tapers to the lowest dose possible to alleviate symptoms, in order to reduce the potential side effects. (Note anabolic steroids used by body builders are a completely different drug and have no application in treating skin disease in dogs.)
• Treatment of concurrent infections; Bacterial and yeast infections are common in dogs with allergies. Antibiotics and antifungals in tablet or injection form, or creams and shampoos are usually used.

Treating skin disease can be frustrating and time consuming at times and generally your dog will never be ‘cured’ but the condition can be managed and controlled.