Skin Disease: Atopy
This is the most common presenting problem in patients I see at Olive Road. Florida ranks number one in the country for Heartworm Disease, Flea Allergy Dermatitis and Atopic Dermatitis. Florida’s tropical climate is a haven for mosquitoes which cause Heartworm Disease, fleas which cause an Allergic Dermatitis and various grasses, pollen, trees and dust mites which cause Atopy. In addition to Flea Allergy Dermatitis and Atopy is Food Allergy Dermatitis which also causes skin disease either alone or in combination with the other two syndromes. So, basically 3 things cause skin disease I see daily in my practice:
Atopic Dermatitis is a syndrome characterized by pruritus or itching. Atopy is an inhaled or contact type allergy similar to hay fever. Florida is a tropical, humid climate which is conducive to heavy pollenQA, thus this syndrome tends to affect pets year round. Other than blooming plants, dust mites, fleas, grasses and trees also contribute to atopic dermatitis.
There are two types of testing for Atopy:
Intradermal skin testing involves injecting small amounts of antigens (allergy particles) under the skin and observing for wheals (allergic responses).
Elisa (RAST) testing involves obtaining a blood sample and sending it to a special allergy lab to be evaluated. This is very common in human medicine, but is not as reliable for animals.
The goal of therapy is to keep the patient comfortably pruritic or itchy. It is almost impossible to rid the pet of all itching, but again the goal is comfort.
Recommended treatment involves treating concomitant disease such as flea allergy and pyoderma (skin infection). Desensitization injections based on Intradermal skin testing or Elisa (RAST) testing provides about a 50% improvement in about 50% of patients. Treatment is usually for the lifetime of the pet. Other studies cite 30% to 70% improvement and treatment cost can be in the several hundred dollar range.
Atopy is very responsive to steroid therapy. Prednisone given on an every other day regimen has proven extremely effective and economical. Most patients need only short infrequent courses of therapy certain times of the year. Side effects include increased thirst, urination and appetite and tend to be does dependent.
Antihistamines are effective in 10% to 30% of cases and may decrease the need for steroids. Examples include hydroxyzine, diphenhydramine, clemastine and others. In my experience, antihistamines have not proven very effective, but are always worth a try before steroid therapy. Another product that may help is Derm Caps (omega 3 and 6 fatty acids) given orally and is also found in some foods (IAMS Lamb and Rice).
Overall, my approach to skin disease involves a step wise progression through these past three months of health columns. I hope these articles have helped you to further understand the etiology and in turn the treatment of the most common diseases seen in veterinary practice.
In the next article, we will discuss Food Allergy.