Diagnosing and managing food allergies: A guide for physicians

A new review aims to help physicians diagnose and manage food allergies in children and adults. The article, published in CMAJ (Canadian Medical Association Journal) looks at recent evidence from guidelines, randomized controlled trials and other research.

An estimated 2% to 10% of people have food allergies, which are more common in children. The prevalence of childhood food allergies has apparently increased; in the United States, the prevalence increased from 3.4% to 5.1% between 1997 and 2011.

Food allergy involves an immune response that can be reproduced and is different from food intolerances, such as lactose intolerance and other nonimmune reactions. Skin reactions are most common in allergy, along with respiratory and other multiorgan symptoms.

Diagnosis can be difficult, but it usually involves a clinical history combined with diagnostic testing, such as a skin prick tests and measurement of serum food-specific IgE (immunoglobulin G) levels. An oral food challenge supervised by an allergy specialist is the gold standard, but it takes time and can result in anaphylactic reactions.

"There is no standardized step-wise approach to testing," writes Dr. Elissa Abrams, Division of Paediatric Allergy and Clinical Immunology, University of Manitoba, Winnipeg, Manitoba, with Dr. Scott Sicherer, Icahn School of Medicine at Mount Sinai, Jaffe Food Allergy Institute, New York, NY. "Skin testing, serum food-specific IgE testing or both may be used to evaluate IgE-mediated food allergies."

The authors caution that food avoidance owing to perceived food "sensitivities" can cause people to eliminate important foods from their diets, resulting in nutritional deficiencies.

"Food-specific [IgG] testing is being increasingly used to identify food "sensitivities,"" they state. "This testing has not been validated nor supported by research."

The review outlines common food allergy symptoms, causes, diagnosis, treatment and management, and immunization guidelines.