Canine Allergic Dermatitis
An itchy dog can be one of the most difficult conditions in veterinary medicine to diagnose and treat effectively. Often, treatment is aimed at a variety of possible causes. In the pursuit of a diagnosis, a complete history is important. Whether the itching is seasonal or all year round, what diet (beef, chicken, fish, lamb, etc) the dog is on, whether we have had any contact recently with other animals, and whether or not any human members of the household have any skin lesions that may have been acquired from your pet, are all factors in determining the cause of the itching.
Medical tests that may be performed include a skin scraping to check for mange, a tape prep to see what secondary infections are present on the skin, a ringworm culture, and serum allergy tests to determine what if anything your dog is allergic to. Generally, dogs that have skin allergies are affected by one or more of the following three agents: 1) by fleas (Flea Allergic Dermatitis), 2) by food (Food Allergic Dermatitis), and/or 3) by inhaled allergens (Canine Atopy).
Flea allergies are relatively easy to diagnose from the physical exam. Keep in mind that it only takes one or two flea bites to get a large area of skin itching for a flea allergic dog. For flea allergic dogs, we recommend Capstar, Advantage, Frontline or Revolution.
A serum allergen test helps us determine whether your dog has canine atopy. Therefore, we recommend doing a serum allergy test to determine the allergens that your pet is allergic to. Having the results to this test allows you to avoid exposure of your dog to those allergens if possible and/or make up an individualized set of allergy vaccines (“allergy shots”) to be given to your dog on a regular basis.
Often we still need to treat your pet’s itching symptomatically with either corticosteroids* (prednisone tablets, dexamethasone injections, etc) or antihistamines (hydroxyzine). If skin lesions are present, an antibiotic is usually also recommended. In addition, we strongly recommend putting your dog on Hills Science Diet Z/D or D/d, or Hills Science Diet Sensitive Skin formula. The Z/D diet is made up of short-chain proteins that are much less likely to cause a food allergic reaction of the skin than other proteins like beef, chicken or lamb. Topical shampoos are also important symptomatic treatments to help your pet feel more comfortable. We recommend Relief shampoo or creme rinse, or Episoothe Shampoo. Oxydex shampoo is helpful if there is a “greasy”, seborrheic feel to the skin. For those dogs with active skin lesions, we recommend Chlorhexiderm shampoo or Hexadene shampoo. You may shampoo up to two times weekly. In addition, DermCaps as an oral supplement are recommended as adjunctive therapy to help your dogs skin problem.
*Corticosteroids, although very effective symptomatic-therapy medications, may cause liver disease after long-term use.
- Sam D. Meisler DVM