Different techniques available for allergy testing

MILWAUKEE—With spring approaching and allergy season in full swing, it is helpful to understand the various methods available for allergy testing, says the American Academy of Allergy, Asthma and Immunology (AAAAI).

Allergy tests provide reliable, specific information about what patients are and are not allergic to. Once the specific allergens causing a patient’s symptoms have been identified, their allergist/immunologist can develop a treatment plan aimed at controlling or eliminating their allergy symptoms, says Thomas B. Casale, MD, President of the AAAAI.

There are two main types of tests available to test for allergies:

• Skin-prick technique: This technique involves introducing a small amount of allergen extract into the skin by making a small puncture. If a patient is allergic, the specific allergens that they are allergic to will cause a local reaction at the site of the test.
  
  People with allergies have an antibody called IgE (immunoglobulin E) in their body which is specific for what they are sensitive to. This antibody attaches to special cells called mast cells. Upon exposure to the substances that a person is allergic to, IgE then binds to the allergens (e.g. cat dander, pollen) and triggers these mast cells to release chemicals called mediators, such as histamine, that cause redness and swelling at the site of the skin test, or allergy symptoms when inhaled. This reaction happens quickly within your body. The results of skin-prick tests are available within 15 minutes of testing, so patients do not have to wait long to find out what is triggering their allergies.

• Blood (RAST) test: Sometimes your allergist/immunologist will do a blood test, called a RAST (radioallergosorbent) test. This laboratory blood test can detect IgE antibodies to specific allergens. This test involves drawing blood, it generally costs more than skin tests, and the results are not available for days. RAST tests are most commonly used in cases in which skin tests can not be performed, such as on patients taking certain medications, or those with skin conditions, such as severe eczema, that may interfere with skin testing. Furthermore, RAST testing is often used to help diagnose food allergies in patients.

Once specific allergies are identified and a treatment plan is in place, patients should see a considerable improvement in their quality of life. Improved sleep quality because of less nasal congestion, days without constant sneezing and nose blowing, improved ability to exercise, and better control of atopic dermatitis (eczema) are some of the improvements patients may gain from allergy treatment plans.

Allergy sufferers can often benefit from seeing an allergist rather than a primary care physician because allergy/immunology specialists are pediatric or internal medicine physicians who have elected an additional two years of training to become specialized in the diagnosis and treatment of asthma, allergies and immunologic diseases. 

The AAAAI represents allergists, asthma specialists, clinical immunologists, allied health professionals and others with a special interest in the research and treatment of allergic disease. Established in 1943, the AAAAI has more than 6,500 members in the United States, Canada and 60 other countries. The AAAAI serves as an advocate to the public by providing educational information and a physician referral directory through its Web site at www.aaaai.org.

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