New Rules for Food Allergies (1)

Fewer Children May Be Diagnosed as Doctors Told Not to Rely Solely on Standard

Skin and Blood Tests

Parents who have eliminated foods from their children's diets based on allergy tests alone may find that some are safe to eat after all. The National Institute for Allergy and Infectious Diseases issued the first clinical guidelines for diagnosing and treating food allergies Monday, saying that blood or skin tests aren't sufficient when making a diagnosis.

An allergy should be suspected if someone has a reaction within minutes or hours of eating a food, according to the guidelines. Physicians should then take a detailed medical history, conduct a physical exam and confirm the allergy with a skin-prick test, in which tiny drops of the suspected allergen are pricked into the skin, usually in the forearm, to see if red wheals form. None of those steps is definitive by itself, the recommendations say, which will likely to lead to fewer diagnoses.

For a correct diagnosis, "it takes a combination, and in some cases an oral food challenge," in which patients are exposed to tiny amounts of the suspect food under close medical supervision, says Hugh A. Sampson, director of the Jaffe Food Allergy Institute at Mount Sinai Medical Center in New York and one of the authors.

The guidelines, published this week in the Journal of Allergy and Clinical Immunology, are aimed at resolving wide discrepancies in diagnosing and treating food allergies among allergists, dermatologists, gastroenterologists, pulmonologists and emergency physicians, as well as pediatricians and internists. More than 30 professional organizations, federal agencies and patient groups were involved in the report, which was in the works for two years. The research company Rand Corp. contributed a review of scientific studies.

Roughly 4% of children under age 18—about three million—reported having food allergies in 2007, an 18% increase from 1997, according to the Centers for Disease Control and Prevention. Milk, eggs, peanuts, wheat, soy, fish and shellfish are the most common culprits, although more than 170 other foods have been reported to cause allergic reactions. Symptoms can range from eczema and hives to asthma, inflammation of the esophagus, diarrhea, vomiting and life-threatening anaphylaxis, in which major body systems quickly shut down.

The prevalence of food allergies has been difficult to gauge because of different standards in diagnosing and a proliferation of tests being marketed to doctors. Some tests have not been scientifically validated, experts say, and some doctors lack the expertise to interpret those that have been. The report did not state that kids were being misdiagnosed, but it did note that erroneous diagnoses could affect their nutritional well-being and quality of life.

Melinda Beck at HealthJournal

Reference information: www.allergy.hk, www.djreprints.com

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