Information from allergy tests may help your doctor develop an allergy treatment plan that includes allergen avoidance, medications or allergy shots (immunotherapy).
Allergy skin tests are widely used to help diagnose allergic conditions, including:
- Hay fever (allergic rhinitis)
- Allergic asthma
- Dermatitis (eczema)
- Food allergies
- Penicillin allergy
- Bee venom allergy
- Latex allergy
Skin testing can be used for people of all ages, including infants. Sometimes, however, skin tests aren't recommended. Your doctor 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 (anaphylaxis).
- Take medications that could interfere with test results. These include antihistamines, many antidepressants and some heartburn medications. Your doctor may determine that it's better for you to continue taking these medications than to temporarily discontinue them in preparation for a skin test.
- Have a widespread skin reaction. 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.
- Have certain skin conditions. Some conditions, including dermographism, urticaria and cutaneous mastocytosis, can cause unreliable test results.
Blood tests (in vitro IgE antibody tests) can be useful for those who shouldn't undergo skin tests. Blood tests aren't done as often as skin tests because they can be less sensitive than skin tests and are more expensive.
In general, allergy skin tests are most 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.