There are many ways that allergies can be evaluated, and some people are not familiar with the different types of tests available. The way that allergy testing is performed has changed slightly over the years, allowing the procedure to be relatively painless for most people. Let’s review the different types of testing done in the allergy clinic!
Skin prick testing: Skin testing, also referred to as “scratch” testing is the most common way that we evaluate allergies. Skin testing involves a small amount of allergens being “pricked” onto the surface of your skin, often with a small plastic device that looks like a toothpick. If you are sensitized to an allergen, this will trigger a reaction on your skin and cause a wheal or hive, similar to an insect bite. Skin testing usually takes about 15 minutes. Skin prick testing is performed for evaluation of possible environmental triggers such as pollens, molds, and animal dander. Skin prick testing is also performed for food allergy if there is a history of allergic reactions to a food (called IgE-mediated food allergy). Skin testing to foods can cause false positives and testing alone does not mean you are allergic to a food. Drug allergies such as penicillin are also evaluated via skin testing.
Intradermal testing: Intradermal testing can also be performed for evaluation of environmental triggers, insect allergy, or drug allergy. This involves a small amount of allergen placed just below the surface of the skin with a very small needle.
Blood tests: Blood tests can be performed for environmental allergens, insect venoms, and food allergies. Blood testing measures allergic antibodies in your blood. Like skin testing, blood testing to foods without a history of reaction to food can sometimes give false positives, and a positive test alone does not diagnose food allergy.
Challenge tests: Challenge tests are done in-office and involve the allergen being taken by mouth (such as foods of drug allergies). Challenge tests are among the most accurate tests to diagnose food allergy, and can help differentiate false positives or if someone has outgrown their food allergy.
Patch testing: Chemical patch testing is a way to evaluate for chemicals or metals that could be causing allergic reactions on the skin. Patch testing involves application of a chemical patch onto the back, with delayed readings in office in 2-3 days or longer, depending on the situation.
Caution!!! There are several tests available over the counter or online labeled as “food sensitivity tests”. These tests are not recommended and do not provide accurate results. Other tests such as food IgG testing, mail-in fingerstick allergy testing, kinesiology muscle testing, hair analysis, ALCAT testing, or neutralization testing are not recommended due to lack of scientific evidence that they correlate with any food allergies.
Your allergy provider will work with you to determine what type of testing is necessary to determine the cause of your symptoms and help guide further treatment.