Allergy and Asthma Doctors | 3 Things to Know About a Patch Test


Allergy and Asthma Doctors | When a patient has been identified as some with allergies, a few different tests may be ordered in order to find the allergy trigger. A Patch Test is a skin test that is designed to detect allergens by placing the allergen directly onto the patient’s skin. Here are some things to know about a Patch Test:

How It Works

The patch is taped to the patients back for 48-72 hours and will be examined by an allergy doctor to see if any reactions have occurred. Each small patch contains a certain allergy substance. The patches are usually lined up in sets of 10 and a few sets may be placed on the patient. Patch testing is usually placed on the patient’s back in order to be easily visible as well as less likely to become disturbed.

What Not To Do

While wearing a patch test, a patient shouldn’t get the patches wet as it could change the test outcome. The patches should stay on the patient and hypoallergenic tape should be used to re-tape the patch if it becomes loose. It is very likely like a patient will experience itching and burning in the small located spot of the patch substance. Patients should not scratch or touch the test area in order to not disturb the testing process.

How Results Are Found

Your allergy doctor will look at the patched area after the test is completed. There are different scores that can be rated onto each allergen spot. These scores include: negative, irritant reaction, uncertain, weak positive, strong positive, and extreme reaction. Only your allergy doctor can accurately interpret and decide what allergens that a patient is allergic to. A red area of tested skin may not mean that a patient is actively allergic to a trigger but that they have had a reaction to it in the past.

A Patch Test is a simple and effective way to test for allergies. It is a great option for those patients who don’t like needles and would rather avoid a skin prick test.


Contact the National Allergy & ENT office today for more information on how a patch test can help you identify your allergy triggers.