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Curious about allergy testing? Here’s how it works

Allergy testing is one of the most important tools allergy doctors have. Test results provide information about what you are, and are not, allergic to. Combined with a full physical examination and complete medical history, the results allow your allergist to tailor your treatment plan and maybe even prevent unnecessary heartache.

For example, perhaps you have allergy symptoms and live in a household that includes a pet. If the allergy tests show an allergy to dust mites but not to pet dander, you don’t have to avoid contact with the pet.

When to get tested
Before doing any allergy testing, your allergist will perform a physical examination and ask questions about your symptoms to confirm that testing is necessary. Symptoms that usually prompt an allergist to perform testing include:

  • Respiratory issues: itchy eyes, nose, or throat; nasal congestion; runny nose; watery eyes; chest congestion; coughing or wheezing
  • Severe allergic reactions: severe reactions to stinging insects or penicillin-based medications
  • Anaphylaxis: a serious allergic reaction that affects many parts of the body at the same time

Types of allergy tests
Adults and children of any age can safely be tested for allergies. Different allergens require different types of tests, and your allergist will help determine which tests are best for you. Tests include:

  • IgE skin tests: This type of testing is the most common and is relatively painless. Very small amounts of certain allergens are introduced into the surface of the skin via small pricks on the back or forearm. If you have allergies, swelling that looks and feels like a mosquito bite will occur where the allergens were placed. Reactions occur within about 15 minutes, and you generally won’t have any other symptoms besides the small hives where the tests were done. Those usually disappear within 30 minutes, though sometimes redness and swelling can occur several hours after skin testing. Patients must stop taking all antihistamines for one week before undergoing this testing.
  • Challenge tests: During this testing, a very small amount of an allergen is taken by mouth or injected. Challenges are performed primarily for potential food or medication allergies. It is very important that these tests be supervised by a board-certified physician with specialized allergy training and experience.
  • Blood tests: IgE blood tests are generally used when skin tests might be unsafe or won’t work, such as if you are taking certain medications, or have a skin condition that may interfere with skin testing.
  • Patch tests: Patch testing is used to help diagnose contact dermatitis and is not painful. During the test, a small amount of an allergen is placed on the back for 48 hours, after which an allergist looks for signs of inflammation.

Once you know exactly what you are allergic to, you and your doctor will be able to develop a treatment plan to reduce or eliminate your allergy symptoms.

Unproven testing methods
Some allergy testing methods are neither useful nor effective, are not supported by research, and may lead to an inappropriate diagnosis and treatment. The American Academy of Allergy, Asthma & Immunology and Vancouver Clinic do not endorse: allergy screening tests performed in supermarkets or drug stores; home testing; applied kinesiology (allergy testing by testing muscle strength or weakness); cytotoxicity or Immunoglobulin G (IgG) testing for food allergies; provocative neutralization testing; or the Rinkel skin titration method.

It is critical that allergy testing is directed by a health care professional with sufficient allergy and immunology training and is prompted by your medical history. Discover if allergy testing might be able to help you better manage your allergy symptoms by making an appointment with an allergy doctor.

Dr. Gregory Owens is an Allergy, Asthma & Immunology Department specialist. He believes in a patient-centered, friendly, and state-of-the art approach to care