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How patch testing can help skin problems

One of the crazy things about skin allergies is that it’s possible to have a reaction to a product that you’ve been using for years. When the skin is chronically exposed to a substance, the body can decide at any point that it doesn’t like it. The reaction usually appears as an itchy, red, or flakey spot. It can be small or cover large parts of the body—particularly when personal care items like shampoo and body wash are involved. What’s more, reactions can happen intermittently. They don’t have to make sense.

When contact dermatitis—or skin inflammation—occurs repeatedly, it’s time to do something about it. Likewise, when parts of the body that aren’t prone to rashes (for example, the face, hands, or eyelids) become irritated, a doctor should investigate further.

Patch testing is usually the best way to discover the source of contact dermatitis. In Vancouver Clinic’s Asthma, Allergy & Immunology Department, we’re able to test for 80 core allergens, which are responsible for 97 percent of patients’ rashes.

Our staff uses special patches that have “wells” that are then loaded with allergens. We apply the patches to the skin, and then the patient comes back after two days to have the skin checked and patches removed. Patients return again at five days for another check. A rash indicates a reaction to the allergen.

Nickel allergies are one of the common ones we see with this test. It’s a metal that’s found in all sorts of products, including makeup brushes and eyelash curlers. Fragrance is another one; it’s in many personal care items. Even neomycin, the antibiotic ointment found in Neosporin®, can cause a reaction.

Once we’ve discovered which allergens are causing the problem we can suggest safe products to use instead. Removing the allergen tends to result in dramatic improvements, with rashes usually improving in one to two months.

Dr. Carrie Caruthers is an Allergy, Asthma & Immunology Department specialist at Vancouver Clinic. She cares for patients of all ages, working with them to create an individualized care plan that allows them to function without limitations.