Diagnosing food allergies is not as foolproof as it should be. Food allergies are less frequent than most people think – only about one in twenty people have a true food allergy. Unfortunately, standard testing for food allergy leads to a significant number of false positive tests – where the test suggests a food allergy exists when it doesn’t.
The Problem with Allergy Skin Tests
Why are tests for food allergies so misleading? The standard for diagnosing food allergies is allergy skin testing. Skin testing involves injecting a small amount of a potential allergen underneath a person’s skin. If a true food allergy exists, antibodies react with the allergen and cause release of histamine which leads to a visible skin reaction. Another way to diagnose food allergies is to measure the antibodies to a particular antigen in a person’s blood. This, too, can give inaccurate results.
So what’s the solution? A company has developed a new way to diagnose food allergies that doesn’t involve allergy skin tests. To do this new form of allergy testing, a sample of blood is drawn and the white blood cells are removed and exposed to the potential food allergen. If a person has a food allergy, the white blood cells will produce more of certain types of molecules called cytokines when exposed to the allergen. By looking at the pattern of cytokines produced, it can be determined whether an allergy to a particular food exists. This new method for diagnosing food allergies should be more accurate than traditional allergy skin tests – with fewer false positives.
Other Tests for Food Allergy
Until this new form of testing for food allergy becomes available, allergy skin tests are still the standard, but there are other lower tech ways to check for food allergies and food intolerences – which can also be used when allergy skin testing is inconclusive. One of the best is to do an elimination diet. This involves eliminating all foods that could be causing the food allergy and gradually adding them back one by one – to see if they cause symptoms. Since most people aren’t allergic to white rice or vegetables, this can be the starting foods – along with lean turkey and chicken. It’s best to do this under the care of an allergist since each allergist has their own unique way of doing an elimination diet.
Testing for Food Allergy: The Bottom Line?
Allergy skin tests are often inaccurate and may over diagnose food allergies. Be on the lookout for this new way of diagnosing food allergies that’s more accurate.
References:
http://web.mit.edu/press/2010/food-allergies.html
