Allergy Testing

What is an allergy test?

Healthcare providers perform allergy tests to determine what substances (allergens) are causing you to have allergy symptoms. Your provider will test how your body reacts to common allergens in a controlled setting during this test.

People can be allergic to things in the environment like mold, pollen and pet dander. Some people have allergic reactions to bee stings or latex. People with food allergies may not be able to eat peanuts, milk or soy without having a reaction.

An allergy test allows your healthcare provider to pinpoint what’s causing the reaction and work on a treatment plan to help manage your allergy symptoms. Allergy tests are safe and effective in diagnosing allergens.

What are the types of allergy tests?

There are different ways to test for allergies. Your allergist will select the best method based on your symptoms, age and what they suspect is causing the allergic reaction.

These tests include:

• Skin prick (scratch) test: Your provider uses a thin needle to prick the skin on your forearm or back with potential allergens. Or your provider may place droplets of potential allergens onto your skin and use a device to scratch and lightly puncture the area, causing the liquid to enter your skin. Reactions such as redness typically occur within 15 minutes of exposure. Your reaction might be a rash or raised, round spots called wheals. This test checks for airborne allergies, food allergies and penicillin allergies. Skin prick tests are the most common allergy test.
• Intradermal skin test: You may get an intradermal skin test if skin prick test results are negative or inconclusive. Your provider injects small amounts of an allergen into the outer layer of your skin (epidermis). This test checks for allergies to irritants in the air, medications and insect stings.
• Patch test: This test determines the cause of contact dermatitis. Your provider places drops of an allergen onto your skin and covers the area with a bandage. Or your provider may apply a patch (bandage) that has the allergen on it. You leave the bandage on and return to the provider’s office within 48 to 96 hours. Then, your provider removes the bandage to check your skin for a rash or other reaction.
• Blood (IgE) test: Your provider sends a sample of your blood to a lab. The lab adds allergens to the blood sample and measures the levels of immunoglobulin E (IgE), an antibody involved in allergies. IgE antibodies in it. A total IgE test measures the total amount of IgE antibodies. A specific IgE test measures how much IgE your body makes in response to a single allergen.
• Oral challenge test: This test occurs only under a provider’s supervision in their office. People with a food or drug allergy swallow (or eat) a small amount of a suspected allergen. An allergist typically performs this test. Medical supervision is a must in order to treat any symptoms that may develop during the challenge.

Why do healthcare providers perform allergy tests?

Your healthcare provider may perform an allergy test if you have allergy symptoms that bother you. Providers also perform allergy tests on people who have asthma. The test can identify allergy triggers that can worsen asthma symptoms (allergic asthma).

You may also need an allergy test if you’ve had a severe allergic reaction called anaphylaxis. This potentially life-threatening problem can cause hives or swelling, breathing difficulty and/or a sharp drop in blood pressure that brings on anaphylactic shock.

Your health history, along with allergy testing, determines the cause of a severe reaction. If you’ve had an anaphylactic reaction or are at risk for one, then you may need to carry an epinephrine (adrenaline) auto-injector (EpiPen®) to use when symptoms develop.

How do I know if I need an allergy test?

Allergies affect everyone differently — this means the allergy symptoms you get can be different from those of your friends, even if you have the same allergy.

If you’re allergic to allergens in the air like dust, pollen or pet dander, you may develop allergic rhinitis. Also known as hay fever, this allergic reaction causes:

• Headaches.
• Itchy, watery eyes.
• Nasal congestion, sneezing or runny nose.
• Shortness of breath, wheezing or chronic cough.
• Sore throat.

Food allergy symptoms typically occur within 30 minutes of eating something but may occur up to two hours after. People with food allergies may experience:

• Skin symptoms such as hives, swelling of the face, lips or tongue, or itching.
• Respiratory symptoms like coughing, wheezing, shortness of breath, chest or throat tightness.
• Nausea and vomiting, abdominal pain and cramps, vomiting and diarrhea.
• Cardiovascular symptoms such as pale skin, weak pulse, dizziness or lightheadedness.

People who are allergic to latex, fragrances or metals like nickel may develop an itchy, swollen rash on their skin. You may have:

• Burning sensation on your skin or blisters.
• Hives and swelling.
• Skin rash or itchy skin.

Contact your healthcare provider if you have any allergy symptoms. They can help diagnose what’s causing your allergic reaction and determine if you need an allergy test. It’s important to not dismiss allergic reactions as just a nuisance. Allergic reactions can be unpredictable and become severe even if your first allergic reaction was mild.