The only way to treat your allergy symptoms is to determine exactly what is causing them. This is done through a series of allergy tests.
What Is a Skin Prick Test?
A skin prick test is the most common form of allergy testing. This test involves placing a small drop of an allergen extract on your skin. A needle is then used to prick the skin underneath the drop; this allows for a small amount of solution to enter just below the surface of the skin. After 15 minutes, any swelling or redness is measured and, depending on the size, is considered a positive reaction.
An intradermal skin test is completed next. An intradermal wheal, or bleb, is injected directly under the top layer of skin. After 15 minutes any reactions are measured and classified as either positive or negative.
How Does a Blood Test Work?
A blood test is used to measure how much of an allergen-specific antibody, called immunoglobulin E (IgE), is in your blood. The more allergen specific IgE in your blood, the more likely you are to be allergic. Blood tests are typically used to confirm the results of a skin test; they may also be used in lieu of skin tests if a serious allergy makes skin testing unsafe.
How Are Food Allergies Tested?
Food allergies may be tested with a simple skin prick test or blood draw. An elimination diet involves removing the food in question from your diet for two to four weeks. If your symptoms resolve, there is a good chance the food was causing the reaction. Your doctor may return the problematic food to your diet, just to make sure the symptoms return.