Overview
During allergy skin tests, the skin is exposed to suspected allergy-causing substances, called allergens, and then checked for signs of an allergic reaction.
Along with a medical history, allergy tests may be able to confirm whether a particular substance a person touches, breathes or eats is causing symptoms.
Why it’s done
Information from allergy tests may help a healthcare professional develop an allergy treatment plan that includes allergen avoidance, medicines or allergy shots, called immunotherapy.
Allergy skin tests are widely used to help diagnose allergic conditions, including:
- Hay fever, also called allergic rhinitis.
- Allergic asthma.
- Dermatitis, called eczema.
- Food allergies.
- Penicillin allergy.
- Bee venom allergy.
Skin tests are generally safe for adults and children of all ages, including infants. In certain circumstances, though, skin tests aren’t recommended. A healthcare professional may advise against skin testing if you:
- Have ever had a severe allergic reaction. You may be so sensitive to certain substances that even the tiny amounts used in skin tests could trigger a life-threatening reaction, known as anaphylaxis.
- Take medicines that could interfere with test results. These include antihistamines, many antidepressants and some heartburn medicines. Your care professional may determine that it’s better for you to continue taking these medicines than to temporarily discontinue them in preparation for a skin test.
- Have certain skin conditions. If severe eczema or psoriasis affects large areas of skin on your arms and back — the usual testing sites — there may not be enough clear, uninvolved skin to do an effective test. Other skin conditions, such as dermatographism, can cause unreliable test results.
Blood tests known as in vitro immunoglobulin E antibody tests can be useful for those who shouldn’t or can’t undergo skin tests. Blood tests aren’t used for penicillin allergy.
In general, allergy skin tests are reliable for diagnosing allergies to airborne substances, such as pollen, pet dander and dust mites. Skin testing may help diagnose food allergies. But because food allergies can be complex, you may need additional tests or procedures.
