When you get a skin rash after contact with an allergy-causing substance (an allergen), doctors call it allergic contact dermatitis. It can be a devastating condition, says Mayo's Mark D. P. Davis, M.D.
"Patients with contact dermatitis can get a very itchy rash from head to toe or in a confined area," Davis says in a news release. "If it's on the hands and feet it can be disabling, and patients at times can't do their jobs."
How do you know what causes your itchy rash? Using a panel of common allergens, doctors put a small amount on a patch of skin and see whether there is a reaction. It's called patch testing.
Davis and other Mayo researchers patch-tested more than 1,500 patients with a series of up to 73 allergens in their study. The top 10 culprits:
Davis reported the findings at this week's annual meeting of the American Academy of Dermatology in San Francisco.
When a patch test is positive, the best thing for patients to do is to avoid the substance to which they are allergic. Treatment with corticosteroid cream can help — but 3% of patients are allergic to the cream, Davis says.
How well does patch testing work from the patient's point of view? In another conference report, Mayo's Leigh Ann Scalf, M.D., and colleagues surveyed about 1,500 patch-test patients.
More than three out of four said they were at least "somewhat satisfied," and more than half said they were "very satisfied." After testing, 58.3% of patients reported improvement in their condition.
Why so few? A third conference report suggests an answer. Davis, Scalf, and Joseph Genebriera, M.D., find that fewer than half of patch-test patients remember all of the things that make them itch.
SOURCES: Davis, M.D.P. Abstract, American Academy of Dermatology, San Francisco, March 3-7, 2006. Genebriera, J. Abstract, American Academy of Dermatology, San Francisco, March 3-7, 2006. Scalf, L.A. Abstract, American Academy of Dermatology, San Francisco, March 3-7, 2006. News release, American Academy of Dermatology.
Daniel J. DeNoon
Reviewed by Louise Chang, M.D.
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