Fran Lowry

November 16, 2010

November 16, 2010 (Phoenix, Arizona) — Delegates to the American College of Allergy, Asthma & Immunology (ACAAI) 2010 Annual Scientific Meeting got a "taste" of new guidelines specifically created to help a wide variety of healthcare professionals, not just allergists, improve their treatment of what some fear is a growing problem in the United States — food allergies.

Funded and coordinated by the National Institute of Allergy and Infectious Diseases (NIAID), the Guidelines for the Diagnosis and Management of Food Allergy in the United States are the result of 2 years of concentrated effort on the part of 34 professional medical organizations, federal agencies, and patient advocacy groups.

Matthew Fenton, PhD, from NIAID's Division of Allergy, Immunology, and Transplantation, in Bethesda, Maryland, told Medscape Medical News that the new guidelines "fill a need voiced by the clinical community to have a set of food allergy clinical practice guidelines that could be distributed and used as a tool by physicians across a variety of clinical specialties."

Food allergy practice parameters in the past were written by allergists for allergists. There was a concern that other healthcare providers who were seeing patients with food allergies, such as family doctors, emergency room physicians, pulmonologists, dermatologists, and gastroenterologists, were using different definitions for food allergy and, as a result, managing the condition in different ways or even missing the diagnosis.

There was also a concern that the true rates of food allergy are difficult to determine.

The NIAID contracted the RAND Corporation to do a systematic literature review of more than 12,000 titles. Of these, 400 were used to prepare an evidence report on the state of science in food allergy, which was then pored over by an expert panel of 25 physicians, nurses, and health educators who drafted the guidelines.

They were posted in the spring of 2010 on the NIAID Web site for a 60-day public comment period, during which 500 comments were received. Many of those comments have been incorporated into the new guidelines.

"That was considered a large feedback," Dr. Fenton said. "The last time the asthma guidelines went up for public comment, there were fewer than 100 comments. So there is a lot of interest out there."

The guidelines detail which tests are useful in making a diagnosis of food allergy and which are not. Specifically, the oral food challenge remains the gold standard to test for food allergy.

"For example, often a physician, [such as] a family practice doctor in a rural setting, would base the definition of food allergy on a clinical history of consistent reactions upon eating the food," said Dr. Fenton. "They couldn't always tell which food was responsible, and they might send out for blood tests to measure total IgE [immunoglobulin E] or allergen-specific IgE levels, but what a lot of physicians don't realize is that abnormally high IgE or the presence of allergen-specific IgE is not diagnostic of food allergy. It just means that you have been sensitized to the allergen."

The guidelines also address the management of severe symptoms, including anaphylaxis. A table outlines primary therapies in both outpatient and inpatient settings, as well as adjunctive therapy, Dr. Fenton said.

"Much to our surprise, we found that many of the other clinical practice areas did not use epinephrine first as the rescue medication, but it's very clear from the literature that epinephrine needs to be used first and it needs to be used repeatedly," he said. "Use of antihistamines as a first response to an anaphylactic symptom simply turns out to be one of the ways that administration of epinephrine gets delayed. If someone comes in with symptoms, even if they have not experienced a serious reaction in the past, you get that epinephrine ready to go."

The guidelines also emphatically state that pregnant women should not restrict their diets because of fears of sensitizing the fetus.

"The idea that peanut sensitization can occur in utero has gotten a lot of press. This has been reported before, but there is no solid evidence that those kids go on to develop clinical food allergy," Dr. Fenton said. "The real concern with infants and pregnant women is to maintain nutritional status. You don't want mothers prophylactically removing foods from their diet simply because they think they might be sensitizing their children."

The NIAID estimates that food allergies affect approximately 5% of children and 4% of adults in the United States and may be increasing in prevalence. But getting a true picture of the extent of the problem is difficult, Dr. Fenton said.

"It's very hard to know what the prevalence is because the numbers that are reported don't really discriminate between food allergy and diseases with very similar symptoms, such as food intolerance and certain gastroenteropathies. Plus, many reports of food allergy are based on simply having IgE levels that are too high or the presence of allergen-specific IgE," he noted.

Changes in food allergy prevalence might be due, in part, to changes in lifestyle and demographics, Dr. Fenton suggested.

"A good example is the increased incidence of kiwi allergy, but that might be due as much to the fact that kiwi is far more available than it was 10 or 20 years ago. A lot of it also may have to do with changes in the population. As new immigrant populations come to this country, they come with their own sets of food allergies," he said.

In addition, NIAID will be preparing a patient and family-friendly synopsis of the guidelines to inform them about food allergy and help them work more closely with physicians.

"The guidelines will be of great help to medical professionals — both specialists and nonspecialists in allergy — because they will make us more homogeneous in the criteria of diagnosis and management of food allergy," ACAAI president Sami L. Bahna, MD, PhD, professor of pediatrics and chief of the allergy/immunology section at Louisiana State University School of Medicine in Shreveport, told Medscape Medical News.

The guidelines will ultimately benefit patients, he added.

"I know our nonspecialist colleagues are very busy, but if they can at least read the summary of the guidelines, I am confident that they will find that their ability to diagnose and manage their patients is improved. And of course, in difficult situations, allergy specialists are available for them," Dr. Bahna said.

The guidelines are set to be published December 6 on the Web site of the Journal of Allergy and Clinical Immunology. Access will be free.

Dr. Fenton and Dr. Bahna have reported no relevant financial interests.

American College of Allergy, Asthma & Immunology (ACAAI) 2010 Annual Scientific Meeting: Presented November 14, 2010.

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