Several types of allergy tests help with asthma, including skin tests and blood tests. The results of your allergy tests may show what's triggering your asthma and allergy symptoms, and that can help with your treatment.
Allergy Skin Tests
Your doctor may recommend skin tests if he or she thinks a specific allergen is causing your asthma symptoms. Allergy skin tests are quick, fairly reliable, and cost-effective. Your doctor will have test results usually within an hour of the skin test.
If you have poorly controlled asthma, trouble breathing, or a high risk of anaphylactic reactions, your doctor may wait to do skin tests.
Ask your doctor if you need to do anything before the test. For example, you should stop taking antihistamines before you get an allergy test. Your doctor may have other specific instructions, too.
In a skin test, you get a dose of a possible allergen. The test tracks your immune system's response -- specifically, if your body makes a molecule called immunoglobulin E (IgE). A high level of IgE can mean you have an allergy.
Skin Prick Test: The skin prick test is the most common allergy skin test. First, you get a series of tiny drops of allergens on your skin, usually on your back. Then you get a quick needle prick in the skin where each of the drops are. If you're allergic, you'll get a dime-sized hive that's red and itchy at the needle prick site. You may need a follow-up test to check the results.
Intradermal Test: If your skin prick test was negative, your doctor may try an intradermal test. In this test, your doctor injects the allergen into your skin. Intradermal allergy tests are often used for environmental allergies and drug allergies. Doctors usually don't use this type of allergy test with food or latex allergies.