Allergists representing three organizations developed evidence-based guidelines for food allergy diagnosis and management, which has become more sophisticated and challenging in recent years due to the increase in prevalence of certain food allergies and important scientific developments.
The Joint Task Force guidelines, “Food Allergy: A Practice Parameter,” are published this month in Annals of Allergy, Asthma & Immunology, the scientific journal of the American College of Allergy, Asthma and Immunology (ACAAI). The Joint Task Force on Practice Parameters, representing the ACAAI, the American Academy of Allergy, Asthma and Immunology (AAAAI) and the Joint Council of Allergy, Asthma and Immunology (JCAAI), has published 20 practice parameters for the field of allergy-immunology.
“The practice parameter on food allergy represents more than 10 years of research and investigation of literature by members of the Joint Task Force,” said Jean A. Chapman, M.D., Cape Girardeau, Mo., a chief editor. “Designed to improve patient care, the guidelines provide practicing physicians with an evidence-based, broadly accepted approach to the diagnostic evaluation and management of IgE-mediated (allergic) food reactions.”
Although adverse food reactions have been reported in up to 25 percent of the U.S. population at some point in their lives, the prevalence of food allergy, an IgE-mediated response to a food, is much lower than the number of suspected food allergies. It varies between 2 percent (adults) and 5 percent (children) in most studies, and is higher in individuals with atopic dermatitis, certain pollen sensitivities or latex sensitivities.
“The guidelines reinforce the need for physicians to think about food allergy as the potential cause of a patient’s symptoms, whether it be GI complaints or skin problems,” said John Oppenheimer, M.D., UMDNJ-New Jersey Medical School, New Brunswick, N.J., a chief editor of the practice parameter.
“Likewise, if a patient has a list of foods they think they are allergic to, it’s important to differentiate what’s truly an allergy and what isn’t. If a patient is trying to avoid 10 or 15 foods, it becomes really cumbersome, and if someone does have an allergy on that list, it is much more difficult to avoid the important allergen,” Dr. Oppenheimer said.
Food allergies are more common in children than in adults. According to the authors, the most common food allergens in infants and young children are cow’s milk, hen’s egg, peanut (a legume), tree nuts, soybeans and wheat. Although sensitivity to most allergens is lost in late childhood, allergy to peanut, tree nut and seafood is likely to continue throughout the patient’s life. Only approximately 20 percent of children with peanut allergy lose their sensitivity. The most common foods causing allergy in adults are peanuts, tree nuts (walnut, hazelnut, Brazil nut, and pecan), fish, crustaceans, mollusks, fruits and vegetables.
“The most important diagnostic tool is the patient’s history. Is there an association between eating the food and having symptoms?” said Jay M. Portnoy, M.D., Section of Allergy, Asthma & Immunology, The Children’s Mercy Hospital; professor of pediatrics, University of Missouri-Kansas City, School of Medicine, Kansas City, Mo.; and associate editor of the practice parameter. “Hidden food allergy is uncommon. Most food allergies occur with a direct relationship - you eat the food, then you have a reaction. It is usually a pretty obvious reaction.”
Due to recent developments in laboratory technology, Dr. Oppenheimer said it has become common practice for physicians to order blood tests for 20 or 30 foods when testing for other allergies, even when there is no history of allergic food reactions. “Being a good historian and culling down what foods you think are important should determine what types of tests are done,” he said.
A detailed discussion of skin prick or puncture tests, serologic tests for specific IgE and oral food challenges is provided in the practice parameter.
“Just because you have a positive test to a food doesn’t mean you are allergic to the food,” Dr. Portnoy said. “It is really important that the symptoms correspond to the test. Personally, I’m still seeing a lot of patients who have been told by a physician not to eat foods because of positive test results, when in fact they have never had a problem with the food. You don’t want to avoid food that you are not allergic to, but you do want to avoid foods that you are allergic to. Allergists can be helpful in determining this because they have special training and experience in interpreting the test results.”
The guidelines recommend carrying more than one epinephrine auto-injector because anaphylactic reactions may be prolonged; to seek immediate medical care after a reaction; and to be monitored for an appropriate period. Most fatal and near-fatal food allergic reactions in the United States are caused by peanut and tree nuts, often with delayed administration of injectable epinephrine.
“The treatment for food allergy is to avoid the food. Inevitably, you’re going to have accidental exposure. It just happens, even to the most careful person. If you’ve got a true, IgE food allergy, you should carry self-injectable epinephrine, even if you’ve only had hives before. The next time if you get a higher exposure, you may have a life-threatening reaction. You should also wear a medical alert bracelet,” Dr. Portnoy said.
The guidelines include recommendations for food allergy management in special settings and circumstances, where patients have an increased risk for unintentional food allergy exposure.
“From the perspective of schools and child care, parents should partner with the administrative staff and teachers or child care workers to determine what avoidance maneuvers may be lacking. It’s important they understand when acute care is needed, how to respond and when it’s appropriate to administer epinephrine,” Dr. Oppenheimer said.
Sections of the practice parameter discuss successful avoidance, risk factors and prevention of food allergy. Cross-reactivity of food allergy, adverse reactions to food additives, genetically modified foods, and future directions also are discussed.
The guidelines list the Food Allergy and Anaphylaxis Network (FAAN) as a resource for patient information on food avoidance. Anne Munoz-Furlong, founder and CEO of FAAN, said the new food allergy guidelines will impact patients in a number of ways.
“First of all, it’s going to give them better and quicker diagnosis of food allergy and that’s going to be a key factor in improving the patient’s and the family’s quality of life,” said Ms. Munoz-Furlong. “I think that while some clinicians are very familiar with food allergy, others rarely see patients with this allergic disorder. The guidelines provide a comprehensive summary and will serve as a good reference tool for both groups of clinicians.
“Additionally, it will improve patient care. Our most common questions from patients are about interpretation of diagnostic tests and whether they should avoid the 30 or so foods their doctor told them to avoid. The information to the clinicians about being careful about diagnostic tests, how to interpret those tests, and being aware of the implications of an over-restrictive diet is going to be an improvement for patients,” she said.
Revision date: June 22, 2011
Last revised: by David A. Scott, M.D.