Food allergies affect approximately 2 million children in the US, according to staff at the Cleveland Clinic. Common food allergens include milk, eggs, wheat, soy and peanuts. Your body produces an immune response when you consume products that you may be allergic to. Your body may produce a mild a mild response like tingling in the throat to a life-threatening response like anaphylaxis. Fortunately, your doctor can administer a number of tests to determine if you are allergic to particular foods.
Skin Prick Test
The skin prick test is used to determine how you react to certain foods. Small diluted samples of the suspected foodstuffs are placed on either your back or your forearm. Your skin is then pricked to allow a small amount of the food sample to penetrate into the outer layer of the skin, the epidermis. If you are allergic to the food sample you'll develop a raised bump or the skin will become red and itchy. The test is the most common test performed to test for a food allergy and is also very accurate.
Radio Allergo Sorbent Test
The Radio Allergo Sorbent Test (RAST) is also known as the Specific IgE test. This is a blood test that measures the level of immunoglobulin E (IgE) in your blood. IgE is an antibody that is produced when you are exposed to food that your body is allergic to. IgE levels tend to be higher in people who suffer from food allergies. The results are graded from a scale of 0 to 6. With a result of 1 indicating a weak positive, and a result of 6 indicating a strong positive. The test can be used to identify up to 400 different allergens.
Atopy Patch Test
Not all allergic reactions cause immediate symptoms. Children sometimes show delayed allergic reactions to allergens such as cow's milk, wheat soy or egg. Delayed reactions to these items include severe eczema, diarrhea, vomiting and reflux. To help identity the food allergens that cause these delayed reactions, a sample of the suspected food allergen is attached to the skin using special aluminum discs, for 48 hours. After another 24 hours the skin is observed for signs of blisters or redness. The test is beneficial but not as effective as the skin prick test in identifying food allergies.
Food Challenge Test
The Double Blind Placebo-Controlled Food Challenge Test (DBPCFC) is done to either confirm or eliminate specific food allergies. During the test, the suspected food is given to the patient in the form of a broth or capsule. The patient is also given a sample that doesn't contain the suspected food allergen. Neither the patient nor the doctor is aware of which sample contains the food allergen and which sample is a placebo. The patient is then carefully observed for a reaction. The food challenge test is done in a specialized allergy clinic or in a controlled environment like a hospital where resuscitation equipment is available. Although the test is one of the most effective, the DBPCFC test is both expensive and time consuming.
