Page 1 of 2Knowing what you are allergic to is the first step in avoiding uncomfortable allergic reactions. While you can learn a lot by trial and error, getting tested by your doctor or allergist will give you a definitive answer, allowing you to receive proper treatment for your allergies.
What is Allergy Testing?
Doctors have been using skin tests to diagnose allergies for more than a century. These tests, which are safe for people of all ages, expose you to a minute amount of allergen, then measure how sensitive you are to the substance.
About ten days before you have a skin test, you will need to stop taking any medications that could interfere with your results. These medications include both over-the-counter and prescription antihistamines (such as fexofenadine and cetirizine), tricyclic antidepressants (amitripyline and doxepin, for example) and heartburn medications (like cimetidine and ranitidine).
Here's a rundown of the three main types of skin tests for allergies:
What to Expect
Skin prick or intradermal tests cause little, if any, pain or discomfort because the needle barely penetrates the skin's surface. With these tests, you'll see an immediate reaction if you are allergic to a particular substance, while reactions to patch tests may take several days to appear. If you're allergic to a substance, a red, itchy bump will develop, much like a mosquito bite. Larger bumps represent a higher rate of sensitivity, while a negative result (no bump) means you probably aren’t allergic to that substance.
The most common side effect of any skin test is redness and itchiness at the site. This usually subsides after a few hours. In rare cases, skin tests can result in a severe allergic reaction. If this occurs, your doctor will have the appropriate medications on hand to treat the reaction. If a severe reaction develops after you leave the office, call your doctor immediately or dial 911 in extreme circumstances.