Patch testing is an allergy test designed to determine if a patient is allergic to a particular topical substance (cosmetics, metals, etc.).
Patch testing is a procedure typically performed over a period of several days. A nurse applies patches, which are a series of stickers containing certain substances to which a patient may be allergic, in the center of the patient’s back. The patches remain on the back for the next 48 hours. The area needs to be kept dry during this whole time. It is unnecessary to stop oral antihistamines for this procedure, but the patient must discontinue any type of oral steroids, including prednisone.
Patch Test Results
After an additional 48 hours, the doctor can then interpret which substance may be a source of skin sensitivity and how to avoid the allergens.