Allergy Testing & Treatments


How do allergy skin tests work?

There are two types of skin tests. During the first type of skin test, a drop of a suspected allergen is pricked on the surface of the skin. The test is performed on the back or forearm. Many suspected allergens are tested at the same time. If you are allergic to one of the tests, you will have redness and swelling at the test spot.

Sometimes the doctor will recommend a second type of test. In this type, a small amount of the suspected allergen is injected into the skin of the arm or forearm. Several suspected allergens are tested at the same time.


How long does it take to get skin test results?

Skin testing is fast. For both types of skin tests, positive reactions usually appear within 20 minutes. Sometimes redness and swelling can occur several hours after skin testing. The delayed reaction usually disappears in 24 to 48 hours, but should be reported to the allergy doctor or nurse.