December 6th, 2010
08:00 AM ET
The first guidelines for diagnosing and managing food allergies were released Monday by The American Academy of Allergy, Asthma and Immunology (AAAAI).
It's a framework intended to help doctors make appropriate decisions about treating patients, but not fixed rules that must be followed. Doctors and patients still need to develop individual treatment plans based on the circumstance of the patient.
The most common food allergens in this country are milk, eggs, peanuts, tree nuts, shellfish, wheat and soy. Milk and eggs are the two most common allergies seen in pediatric patients, but 80 percent of children outgrow them.
Peanuts, treenuts and shellfish allergies more often last a lifetime–less than 10-20 percent of kids outgrow them according to Dr. Hugh Sampson, Professor of Pediatrics at Mount Sinai School of Medicine and a member of the Guidelines Coordinating Committee.
Sampson says food allergy is often overdiagnosed. In fact, he says one of the most common problems is confusion over whether a patient has food sensitivity - a reaction to foods that does not involve the immune system - or true food allergies. Some of the symptoms are the same.
"A lot of doctors order large numbers of blood tests to various foods and when they find small amounts of antibodies present they indicated allergic reaction," Sampson said, leading to children being put on very highly restricted diets. "The exercise of diagnosing a food allergy is not just doing a skin test or blood test. It takes a combination of patient history, and oral food challenges."
An oral food challenge is when a food is given to a patient in a controlled setting to watch for a reaction. Sampson says many doctors don't perform oral tests because it's time consuming, and there is some risk involved.
A set of 18 guidelines address diagnosis. For example, when food allergies should be considered: If a combination of symptoms like hives, chest tightness, wheezing, tongue swelling occur within minutes to hours of eating, or if symptoms occur more than once after eating a specific food.
Other diagnosis recommendations include doing a physical exam, using a patient's medical history and doing a skin puncture test (SPT) the most common skin test, in which the skin is scratched or pricked with very small amounts of the allergen.
The guidelines do not recommend intradermal testing. In an intradermal test, a small amount of the suspected allergen is injected under the surface of the skin. After about 20 minutes the skin is examined for any reaction such as redness and swelling. An atopy patch test (APT), where a sticky patch is attached to the skin for up to 48 hours, should not be used.
Other guidelines address who is at risk, how to manage non-serious reactions and how to prevent allergies. There are detailed guidelines on diagnosing and treating life-threatening, food-induced allergic reactions like anaphylaxis, a serious reaction that happens quickly and can be deadly. Epinephrine, according to the report, is the first line of treatment in all cases of anaphylaxis. All other drugs have a delayed response.
Dr. Matthew Fenton oversees allergic diseases research for the National Institutes of Allergies and Infectious Diseases at the National Institutes of Health and served on the Coordinating Committee. He says the agency is now working on a summary for consumers.
"It's important for patients and their families to understand that the symptoms of food allergy can mimic several other very legitimate diseases such as food intolerance and gastrointestinal problems. It is important for them to work with their doctors so they can identify the true root cause of the health affect caused by food."
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