Allergy

To evaluate whether you have an allergy, your doctor will likely:

Ask detailed questions about signs and symptoms

Perform a physical exam

Have you keep a detailed diary of symptoms and possible triggers

If you have a food allergy, your doctor will likely:

Ask you to keep a detailed diary of the foods you eat

Ask if you've stopped eating the suspected food during the allergy evaluation

Your doctor might also recommend one or both of the following tests. However, be aware that these allergy tests can be falsely positive or falsely negative.

Skin test. A doctor or nurse will prick your skin and expose you to small amounts of the proteins found in potential allergens. If you're allergic, you'll likely develop a raised bump (hive) at the test location on your skin.

Blood test. Specific IgE (sIgE) blood testing, commonly called radioallergosorbent test (RAST) or ImmunoCAP testing, measures the amount of allergy-causing antibodies in your bloodstream, known as immunoglobulin E (IgE) antibodies. A blood sample is sent to a medical laboratory, where it can be tested for evidence of sensitivity to possible allergens.

If your doctor suspects your problems are caused by something other than an allergy, other tests might help identify — or rule out — other medical problems.

Allergy treatments include:

Allergen avoidance. Your doctor will help you take steps to identify and avoid your allergy triggers. This is generally the most important step in preventing allergic reactions and reducing symptoms.

Medications. Depending on your allergy, medications can help reduce your immune system reaction and ease symptoms. Your doctor might suggest over-the-counter or prescription medication in the form of pills or liquid, nasal sprays, or eyedrops.

Immunotherapy. For severe allergies or allergies not completely relieved by other treatment, your doctor might recommend allergen immunotherapy. This treatment involves a series of injections of purified allergen extracts, usually given over a period of a few years.

Another form of immunotherapy is a tablet that's placed under the tongue (sublingual) until it dissolves. Sublingual drugs are used to treat some pollen allergies.

Emergency epinephrine. If you have a severe allergy, you might need to carry an emergency epinephrine shot at all times. Given for severe allergic reactions, an epinephrine shot (Auvi-Q, EpiPen, others) can reduce symptoms until you get emergency treatment.