Friday, January 28, 2011

Food Allergies

How many times have you heard someone say that they are allergic to a specific food? Food allergies are indeed common, affecting roughly 8% of kids and around 4% of adults. A true food allergy is an immune reaction to a food protein. There are many food REACTIONS (such as lactose intolerance, for example) that are not true allergies.The most common allergens are PEANUT, FISH, SHELLFISH and other TREE NUTS.

What are signs and symptoms? Food allergies show up within minutes to a couple hours after exposure to even small amounts of the offending protein. Itchy, red rashes, swelling, flushing, nausea, abdominal cramping and diarrhea, stuffy nose, wheezing, racing heart and metallic taste in your mouth are some of the possible presentations.

How do we diagnose food allergies? Mainly by history, to be honest. We combine the history with either skin or blood testing for more accuracy. Skin testing CAN be helpful, but there are many false-positives (which means the test says there IS an allergy, but there is not.) NEGATIVE results on a skin test, however, are very accurate that there is NO food allergy, so that can be very reassuring. Blood tests are also poorly predictive, being accurate only roughly half of the time. We do know, though, that high levels of blood tested antibodies are very suggestive of an allergy to that food.

We do not have a CURE for food allergies, but we can use antihistamines and epinephrine to treat acute reactions.
Of course, the mainstay of treatment is prevention through avoidance of that food protein.

BOTTOM LINE: If you think you may have a true food allergy, discuss it with your doctor and consider additional testing before permanently restricting your diet.

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