Patch testing is another type of test offered at Allergy, Asthma, and Sinus Center of Long Island. This is a test we use for contact dermatitis. What is contact dermatitis? Think of something touching your skin and your skin then developing a rash sometimes even 72 hours later. The most well-known example of this is the reaction people have after exposure to poison ivy—the poison ivy touches the person’s skin and they start exhibiting the rash afterwards. But someone can have contact dermatitis from several things besides poison ivy. A chemical found in hair dye, chemicals found in lotions and cosmetics, and even metal! To assess for a possible contact dermatitis, we start by applying patch testing to someone’s back, having them come back a few days later to remove the test, and then we have them come back a few days after that to look at the back again. A contact dermatitis can be delayed and doesn’t have to cause an immediate rash which is why we have patients come back for a third visit because what is positive on the third visit may not have been positive on the second visit. We offer a patch test that can test for 80 different things. If you are interested, make an appointment today!