Our homes, workplaces and environments contain many substances that can irritate our skin or cause an allergic reaction called contact dermatitis. While allergic contact dermatitis is common, you don’t have to suffer in itchy silence. A patch test—which tests for allergic reactions that typically develop over several days— is often the most effective way to eliminate guesswork and relieve your symptoms of allergic contact dermatitis.
Tufts Medical Center dermatologist, Rebecca Dufner, MD, FAAD shares who benefits from patch testing and what you can expect.
Your doctor may recommend patch testing if you have any of the following conditions:
- Chronic dermatitis: Patch testing can identify potential allergens in people who experience persistent or recurrent dermatitis that does not respond to standard treatments.
- Occupational dermatitis: People exposed to chemicals, metals or other substances that may cause skin reactions, such as hairdressers, healthcare workers and construction workers, can use patch testing to pinpoint the cause.
- Eczema: Patch testing can help identify and eliminate triggers for people with atopic dermatitis who suspect contact allergens might be exacerbating their condition.
- Unexplained skin reactions: Anyone experiencing unexplained rashes, redness, itching or other skin issues that do not clear up with typical treatments.
- Cosmetic or personal care product reactions: People who develop skin reactions to cosmetics, skincare products or personal hygiene items can use patch testing to determine which specific ingredients are problematic.
What to expect during patch testing
- Initial consultation: During your first visit, a dermatologist will review your medical history, perform a physical exam and discuss your symptoms. This helps your doctor determine whether patch testing is likely to be helpful for you.
- Applying the patches: At your initial patch testing appointment, your doctor will take a detailed medical history to help her determine which allergens to include in your patch test. Small patches containing potential allergens will be applied to your back. Depending on your exposure history, this usually consists of a customized panel of 100-150 allergens. These patches are secured with hypoallergenic tape and will remain in place for 48 hours.
- First follow-up visit: After 48 hours, you can return to the office to have the patches removed or remove the patches at home with the help of a partner or friend who can assist in taking photos of your skin. We will document any early reactions.
- Final read and discussion of results: A final follow-up is scheduled 1 week after the patches were placed to evaluate for delayed reactions. Many allergens may cause a reaction several days after the original exposure. Your doctor will interpret the results and discuss any positive reactions with you. You will receive guidance on how to avoid identified allergens, find skin-safe products and manage your dermatitis.
Tips for getting the most out of your patch test:
- Avoid getting your back wet: During testing, you will need to avoid activities that may wet the patches and your back, such as swimming, showering, and heavy sweating.
- Do not scratch: If you experience itching, try not to scratch your back. You can take an over-the-counter antihistamine or apply ice packs to soothe your symptoms.
- Wear comfortable clothing: Choose loose-fitting clothes to prevent the patches from being disturbed and increase your comfort.
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