Many patients with allergic contact dermatitis (ACD) have itchy, red patches appearing suddenly or over a period of time, and Dermatologists are tasked with figuring out why.
ACD usually consists of symmetrical patches in locations such as the top of the hands or around the eyes, from an unknown allergen touching the skin and causing a reaction. Sometimes we can narrow down the culprits based on the patient’s habits or occupation.
While treatments consist of oral and topical steroids, if the patient remains in contact with the allergen, the rash may persist. Our office accepts many referrals for what is called “patch testing.” No needles are involved!
Patch testing consists of a known series of allergens placed in chambers and applied to the patient’s back. We use 80 common allergens, including substances such as nickel, formaldehyde, beeswax, Vitamin E, and lanolin. Once the patches are applied to the patient’s skin, they are kept on for 48 hours without getting them wet.
After two days, the patient will return to the office where we remove the patches and “read” the test. A positive reaction consists of finding a reaction/rash on the skin in the boxed area of the tested allergen. We also read the test results later in the week often through emailed photos, and then again in person.
In this way, we can often identify the substance a patient can avoid to prevent their rash. Once an allergen is found, patients can become their own skin detective and try to find and eliminate the allergen in any of their personal care products.
It can be quite satisfying!
Dr. Schwarz, a board-certified Dermatologist, is also a member of the American Contact Dermatitis Society.
Contact the office to schedule an appointment at 215-589-7373. www.schwarzderm.com.
PHOTO CAP: Patch testing provides a pain-free way to determine causes of skin allergies.