Allergy testing

Every time you walk into your backyard, you start sneezing, sniffling, and feeling like you want to go back indoors. You're pretty sure you have an allergy, but what are you allergic to? Pollen? Grass? Your neighbor's Golden retriever? The only way to know for sure what's making you sneeze is to have allergy tests at your doctor's office. Let's talk about allergy testing.

Your doctor may do one or more of several different types of allergy tests to see what's causing your allergies. One is a skin test. It can diagnose allergies to things like mold, pollen, animal fur, insect stings, and foods.

With a skin test, your doctor will place a small amount of one substance, or several different substances just under the surface of the skin on your arm or back. You'll feel a little prick when the substances are placed under your skin. After 15 minutes or so, the doctor will look for signs that you're having a reaction. Usually your skin will get red or swollen if you're allergic to something in the test.

Another way to test for allergies is to put a patch of the substance on your skin and leave it there for about 2 days, checking the area every day for any sign of a reaction.

You may have a blood test. A blood test measures the amount of substances called antibodies that your body produces in response to a certain allergen.

If you're allergic to food, you can try avoiding whatever foods you think might be making you sick. This is called elimination testing. Then you add back in each of the foods, one at a time, and look for signs of an allergic reaction.

Your doctor may also try to trigger an allergic reaction in the office by having you eat the food or breathe in the substance you think causes your allergy. This is called a challenge test. The one risk to this test is that, if you're severely allergic, you could have a very serious reaction. Your doctor will watch you very closely during this test to make sure you're safe.

Allergy tests are usually pretty accurate. But sometimes what bothers you in the real world won't show up on the test. If you have one test and it doesn't find your allergy trigger, your doctor may recommend having another type of test. Don't worry if it takes a while to find the source of your allergies. Your doctor will keep trying different methods until you learn exactly what's making you so miserable.

Version Info

  • Last reviewed on 10/25/2011
  • Alan Greene, MD, Author and Practicing Pediatrician; also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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