March 3, 2014
Children Who Outgrow Allergies May Have Severe Recurrences
Lawrence LeBlond for redOrbit.com - Your Universe Online
Children who outgrow a food allergy are not always out of the woods. In some cases, an allergy to the same food can return, often becoming more severe and more persistent.
Pediatric allergy experts with the Children’s Hospital of Philadelphia (CHOP) have reached out to healthcare providers and caregivers, asking them to carefully monitor children with food allergies for early signs of eosinophilic esophagitis (EoE), a severe and painful type of allergy that has been increasingly more common in recent years.
"These two types of allergy have some elements in common, but patients with EoE usually don't go on to develop tolerance to the foods that trigger EoE," pediatric allergist Jonathan M. Spergel, MD, PhD, a pediatric allergist with CHOP, said in a statement.
Spergel is also director of CHOP's Center for Pediatric Eosinophilic Disorders, one of the top programs in the nation for EoE treatment.
His research was presented today at the annual meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) in San Diego by Solrun Melkorka Maggadottir, MD, also of CHOP.
EoE involves swelling and inflammation of the esophagus, along with excessive levels of immune cells called eosinophils. EoE is known to cause weight loss, vomiting, heartburn and difficulty swallowing. This painful disorder affects people in any age group, but is usually first discovered in children with feeding difficulties.
Spergel and colleagues compared EoE with IgE-mediated food allergy, a more familiar type of food allergy that occurs when antibodies mount an exaggerated immune response against proteins in particular foods, such as nuts, eggs or milk. These foods can trigger a host of problems, including vomiting, hives and other skin reactions.
For the study, the team performed a retrospective analysis of 1,375 children seen at CHOP for EoE between 2000 and 2012. Of those, 425 could be shown to have a definite food causing their disorder – most commonly milk, egg, soy, or wheat. Of these children, 17 had gone on to develop EoE to a food after outgrowing IgE-mediated allergy to that same 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 Spergel. "However, this pattern also raises the possibility that prior IgE-mediated food allergy may predispose a patient to developing EoE to the same food."
About 10 percent of patients who undergo desensitization therapy for IgE-mediated food allergies go on to develop EoE to the same food, noted Spergel.
He added this is a high enough percentage that healthcare providers and caregivers need to consider it when treating patients with food allergies.
In desensitization therapy, a clinician exposes a patient to miniscule amount of an allergy-producing food, then gradually increases the amount, aiming for the patient to become tolerant to that food.
This desensitization therapy has been shown to be hugely successful in some children with peanut allergies.
Researchers from University of Cambridge reported in January that they were able to offer 84 percent of children with peanut allergies in their study group the ability to eat the equivalent of five peanuts per day after six months of desensitization therapy.