Vitamin A-Responsive Dermatosis in a Canineby Deborah Lundin
Skin conditions are common in dogs, and the causes vary. Most often poor skin condition is due to allergies or bacterial, viral or fungal infection. "Vitamin A-responsive dermatosis" is a rare skin condition that causes scaly and crusty skin with no known cause. Treatment is available through a veterinarian, and it is often required for the life of the dog.
Symptoms of vitamin A-responsive dermatosis typically surface on the dog’s chest and abdomen. Small lesions and crusty plaque develop on the surface of the skin. Hair in this area often protrudes through clumps of skin cells. The coat may become dull and dry, and his ears may show signs of excess wax and inflammation. Hair loss, or alopecia, is common in affected areas. Secondary bacterial infections and yeast infections of the skin, which cause foul odor and itching, are also common.
Causes and Predisposition
The cause of vitamin A-responsive dermatosis is unknown; however, genetics may play a role. The condition almost exclusively occurs in American cocker spaniels and develops between the ages of 2 and 3 years. While the condition responds to vitamin A treatment, the dog’s diet is typically not vitamin A deficient. It is recommended that dogs diagnosed with the condition be removed from the breeding pool in order to reduce the risk of passing it down to puppies.
Because symptoms of vitamin A-responsive dermatosis are similar to other skin conditions, a veterinarian must first rule out other infections or allergies. A veterinarian will perform a skin biopsy to help rule out other possible causes. Because treatment involves high doses of vitamin A, it is important to rule out any underlying causes. If an infection or allergies are the cause, treatment with vitamin A can lead to vitamin toxicity.
The treatment for vitamin A-responsive dermatosis is high dosage of vitamin A. Typically, a veterinarian prescribes 10,000 IU/d orally each day with a meal. This amount far exceeds the recommended daily amount of vitamin A for dogs -- that's why it's important to have an accurate diagnosis from a veterinarian. Typically, symptoms improve within six to eight weeks, though treatment often must continue for the rest of the dog's life. Should secondary skin infections or yeast infections occur, treat with antibiotics or antifungals.
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