Allergy Tests

The diagnosis of allergies, or allergic disease, is based on the clinical history, family history, physical examination, skin tests and laboratory tests. The tests serve to confirm the diagnosis of allergic disease and to identify potential allergic triggers, including food allergens, knowledge that is useful to guide allergen avoidance strategies.

When you see an allergy specialist, allergy tests will likely be performed to determine whether you are allergic and what the allergen is. Skin prick tests are carried out by applying drops of allergens to your skin, usually on your back and occasionally on your arm, and then scratching or pricking through them. Skin tests are used to test for allergies to environmental allergens, such as pollens, molds, dust mites and animal dander, as well as foods. If you are allergic to an allergen, you will get a bump and redness where the skin is pricked. After a short time, each skin test reaction is measured for swelling and redness. A large enough skin reaction is a positive skin test. This means an allergy may exist to the allergen placed at that site. Your doctor will compare your skin prick test results with your history of symptoms.

Allergy blood tests evaluate for sensitizing IgE antibodies that bind to environmental and/or food allergens and may be performed if skin testing cannot be done, or to gain additional information.

Allergy History

Allergy testing begins with careful questioning to compile a personal and family history. Your history is a very important first step in treating your allergic condition. These are some of the questions that your doctor may ask you during this process:

• What symptoms are you experiencing?
• Do your symptoms appear and/or worsen when you are at a particular location, during a given season of the year or at a specific time of day?
• How long have you experienced your symptoms?
• What kind of work do you do? What sort of things are you exposed to at work?
• Are there pets in your home?
• What are your hobbies?
• Do any other family members have an allergic condition?

You may want to think about your answers to these questions beforehand, so that you can give the most complete and accurate information to your doctor. These questions may help to reduce the list of suspected allergens and tests needed to evaluate your condition.