Vitamin A-Responsive Dermatosis
Vitamin A-responsive dermatosis is not a systemic vitamin A deficiency, but a local deficiency in the skin, a disorder of skin utilization, or a pharmacological effect of high doses on the skin. Anything that interferes with the absorption with vitamin A or enhances its excretion can result in a relative deficiency. However, since oversupplementation can result in toxicity, the levels of vitamin A administered should be carefully monitored.3 Vitamin A-responsive dermatosis is most frequently seen in the Cocker Spaniel, Labrador Retriever, Miniature Schnauzer, and Shar-pei.
Clinical signs are usually present by 2 to 3 years of age and are very similar to those seen in idiopathic seborrhea. Affected dogs have recurrent scaling, dry hair coat with easy epilation, and prominent comedones. Plaques are most prominent on the chest and abdomen. Ear infections and itchiness are common. A preliminary diagnosis is made from skin biopsy findings. However, even with the classic clinical findings, a definitive diagnosis can be confirmed only by the response to supplementation with vitamin A alcohol, which is prescribed for the life of the patient. Improvement is seen within 4 to 6 weeks. Complete remission is obtained by 10 weeks of treatment and is well-tolerated. Medicated shampoos containing benzoyl peroxide (oxyDex, Sulf OxyDex, Pyoben) have excellent follicular flushing activity. Twice to three times weekly usage helps remove keratinous debris from follicles and hastens recovery.
- Scott, Miller, Griffin. Small Animal Dermatology, 5th ed., Philadelphia, WB Saunder
- Nesbitt & Ackerman. Canine & Feline Dermatology, 1st ed., New Jersey, Veterinary Learning Systems
- Lowell Ackerman. Nutritional Supplements in Canine Dermatoses