An allergy is an immune system overreaction to triggers that are usually harmless, like pollen, food, or medicine. Allergy testing is a way to check what triggers your immune system. 

These tests help your care team confirm what’s causing your symptoms so you can avoid triggers and receive the right care. You may undergo one or more of these types of tests, depending on your symptoms:

• Allergy skin testing: The tester places a small amount of an allergen on your skin. If you’re allergic, a small red, itchy bump may appear. Results are usually ready in about 15 minutes.
• Drug allergy testing: This test checks whether you react to certain medicines. It may include skin testing, or the care team will monitor you after you take a small dose of the medicine. They watch for reactions and help you plan safe medicine use in the future.
• Food allergy testing: Tests for food allergies may include skin tests, blood tests, or a supervised oral challenge. These tests help your care team know which foods you’re allergic to and guide their suggestion to prevent serious reactions in the future.
• Patch testing: These tests look for delayed skin reactions. Nickel, fragrances, and other contact allergens may cause this type of reaction. The care team places small patches with the triggers on your skin that stay on for 48 hours. They check your skin for redness, bumps, and irritation over several days.

Allergy testing can help you identify allergy triggers. It can also help if you have ongoing reactions you can't explain.

Testing is often suggested for the following conditions:

• Food allergies: Food allergies can cause serious reactions and require urgent medical attention. Knowing the foods you’re allergic to can help you avoid them.
• Environmental allergies: Because you can't always avoid triggers like dust, testing helps guide treatments. You may be able to get allergy shots, which can provide long-term relief.
• Seasonal allergies: When you know which type of pollen affects you, you can start taking allergy medicine before your symptoms start.
• Medicine allergies: Testing is available for some medications and helps confirm which medicines are unsafe. This helps you avoid serious reactions in the future. Did you know that you may outgrow a penicillin allergy? If you have a penicillin allergy, testing can help identify if this is still a problem for you.
• Venom (insect sting) allergies: Testing can help your doctor know if you’re at risk for a severe reaction to a sting. It helps guide your care plan if you’re stung again.

Before the test

Your doctor will review your symptoms and explain which tests you will have.

Some medications can interfere with allergy testing. Your care team will review your medications with you and let you know if any need to be stopped for up to a week before your test. This helps make the skin test results more accurate.

During the test

Most allergy tests happen in the clinic and take 30 to 60 minutes. Occasionally, testing may be longer.

• Skin tests: Your care team will give your skin small pricks of allergens to see how your body reacts.
• Patch test: The care team places patches of allergen on your skin, and you go home with them in place. You return after 48 hours so your care team can check your skin for reactions. A second follow-up visit happens a few days later.
• Blood tests: These tests involve a simple blood draw.
• Oral challenge: Your care team watches you closely as you receive small, increasing amounts of a food or medicine in a controlled setting.

After the test

Your care team will go over the results with you. You may have mild itching or redness after skin testing, but this usually fades quickly. You will get guidance on managing your allergies. Treatment may include avoiding triggers, taking medicines, or getting treatments like allergy shots or biologics.