Newly recognized as a distinct condition, eosinophilic esophagitis (EoE) is a severe and often painful type of allergy that has been increasing in recent years. EoE is characterized by the presence of large numbers of white blood cells called eosinophils in the tissue of the esophagus, which causes inflammation or swelling.

A study by allergy experts at The Children's Hospital of Philadelphia compared EoE with IgE-mediated food allergy - the more familiar type of food allergy that occurs when antibodies mount an exaggerated immune response against proteins in particular foods and trigger skin reactions, vomiting, or other symptoms.

The researchers performed a retrospective analysis of all children seen at CHOP for EoE between 2000 and 2012, a total of 1,375 patients. Of that number, researchers identified 425 children with a definite food causing their condition - most commonly milk, egg, soy, and wheat. Within that subgroup, 17 patients had developed EoE to a food after having outgrown IgE-mediated allergy to that specific food.

"The pattern we found in those 17 patients suggests that the two types of food allergy have distinct pathophysiologies - they operate by different mechanisms and cause different functional changes," said Jonathan M. Spergel, MD, PhD, director of CHOP's Center for Pediatric Eosinophilic Disorders, one of the nation's premier programs for these conditions. "However, this pattern also raises the possibility that prior IgE-mediated food allergy may predispose a patient to developing EoE to the same food."

The researchers suggest that healthcare providers and caregivers carefully monitor children with food allergies to recognize early signs of EoE.

Dr. Spergel is the senior author of the research, presented recently by Solrun Melkorka Maggadottir, MD, also of CHOP, at the annual meeting of the American Academy of Allergy, Asthma & Immunology in San Diego.