Q. I have hand eczema that is red, scaly and itchy. My doctor thinks it’s “contact dermatitis” and is sending me for patch testing. Can you tell me about the condition and test? FYI, I’m a caterer, so I do wash my hands a lot.
Dr. Skotnicki: Contact dermatitis is a common medical issue, and often job-related. It will occur in occupations where there is exposure to irritants such as soap and gloves – and less frequently due to true allergic reactions to chemicals.
Contact dermatitis encompasses both irritant contact dermatitis and allergic contact dermatitis.
The test to determine whether a chemical is causing an irritant rather than an allergic reaction is called patch testing. This is not what an allergist does when they prick your inner arm. Skin-prick testing, as that is known, determines allergy to things you consume or inhale, such as peanuts or ragweed.
Patch testing determines allergy to a chemical contacting your skin. For this test, patients have to visit the dermatologist three times over a week.
On day one, chemicals are applied to the back and covered with paper tape. On day three they are removed, and on day five the back is examined for signs of eczema. If there is a reaction, the patient has tested positive to that chemical and it could be the cause of their eczema.
As a caterer, you most likely have irritant contact dermatitis due to frequent hand-washing and glove-wearing. It’s important to have patch testing to rule out a true allergy to ingredients in the soap or rubber (latex) as the cause. If the test is negative, you likely have irritant contact dermatitis. Treatment for this condition involves decreasing your irritant exposure and treating the eczema with proper medication.
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