Testing For Food Allergies
Kristine Napier, M.P.H., R.D., L.D.
Nutrio.com Team If you think you have a food allergy, see a doctor right away. Don't try to diagnose the problem yourself. Many people who do, place themselves on overly restrictive diets, which can result in nutritional deficiencies. Testing for allergies, however, is not an easy task. The only sure way to know if someone has a food allergy is to feed them the suspected offending food or foods. Experts warn that this food challenge, as it is called, should only be done only under a doctor's watchful eye and in the presence of emergency medical equipment. Short of feeding the suspecting food, food allergies are identified in other ways. Taking a careful history is the first-line strategy in diagnosis. People with suspected allergies are also asked to keep a food diary, which can be invaluable. This helps determine which food is responsible, how quickly it produces symptoms and what types of symptoms it causes. Skin and blood testing can provide useful clues to food allergy. In skin testing, doctors place small amounts of the suspected food allergen into a small scratch or puncture on the skin and watch for a reaction. If redness and swelling result, that person may be allergic to the food causing the reaction. While a negative skin test is very reliable, a positive skin test is less so. Skin tests can produce false positive results, or suggest an allergy when one doesn't exist. Two blood tests, the radioallergosorbent test or RAST and the enzyme-linked immunosorbent assay or ELISA can also provide helpful information in diagnosing food allergies. Beware of two controversial testing methods, say experts at the American Academy of Allergy and Immunology. In cytotoxic testing and symptom provocation testing, a small amount of an extract made with the suspected food is placed under the tongue. These methods are not only expensive, but are quite unreliable.
Nutrio.com Team If you think you have a food allergy, see a doctor right away. Don't try to diagnose the problem yourself. Many people who do, place themselves on overly restrictive diets, which can result in nutritional deficiencies. Testing for allergies, however, is not an easy task. The only sure way to know if someone has a food allergy is to feed them the suspected offending food or foods. Experts warn that this food challenge, as it is called, should only be done only under a doctor's watchful eye and in the presence of emergency medical equipment. Short of feeding the suspecting food, food allergies are identified in other ways. Taking a careful history is the first-line strategy in diagnosis. People with suspected allergies are also asked to keep a food diary, which can be invaluable. This helps determine which food is responsible, how quickly it produces symptoms and what types of symptoms it causes. Skin and blood testing can provide useful clues to food allergy. In skin testing, doctors place small amounts of the suspected food allergen into a small scratch or puncture on the skin and watch for a reaction. If redness and swelling result, that person may be allergic to the food causing the reaction. While a negative skin test is very reliable, a positive skin test is less so. Skin tests can produce false positive results, or suggest an allergy when one doesn't exist. Two blood tests, the radioallergosorbent test or RAST and the enzyme-linked immunosorbent assay or ELISA can also provide helpful information in diagnosing food allergies. Beware of two controversial testing methods, say experts at the American Academy of Allergy and Immunology. In cytotoxic testing and symptom provocation testing, a small amount of an extract made with the suspected food is placed under the tongue. These methods are not only expensive, but are quite unreliable.
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