The Children’s Hospital of Philadelphia, seen at night.
A small proportion of children who outgrow a food allergy will a few years later develop symptoms of eosinophilic esophagitis or EoE to that same food, according to research from the Children’s Hospital of Philadelphia.
Dr. Solrun Maggadottir and colleagues analyzed data on 1,025 patients at CHOP’s Center for Pediatric Eosinophilic Disorders, which included 84 patients who reported also having (or having had) a “true” food allergy, the kind mediated by IgE antibodies.
Seventeen of those patients had naturally outgrown the IgE allergy (to peanut, nuts, egg or milk) before arriving at the clinic with EoE symptoms. But having reintroduced the food into their diets, these 17 developed EoE to the same food trigger, Maggadottir explained in presenting the study at the 2014 AAAAI meeting.
“Two to four years later, they come back with this unique and different food allergy – now they’ve got eosinophilic esophagitis to the same food,” Dr. Jonathan Spergel, director of the eosinophilic disorders center and a study co-author, explained to reporters at a media conference. “Instead of getting anaphylaxis to this food, now the esophagus is getting swollen to the same food.”
In EoE, high levels of eosinophil cells congregate in the esophagus, leading to the chronic inflammation. In children, the more obvious symptoms are gastrointestinal, such as severe abdominal pain and vomiting. If not diagnosed, as kids get older “they get really bad reflux symptoms, as they get older still, the esophagus gets narrower and swollen, they get food impaction and food gets stuck,” said Spergel.
“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,” he said. “However, this pattern also raises the possibility that prior IgE-mediated food allergy may predispose a patient to developing EoE to the same food.”
Dr. Jonathan Spergel
As a leading EoE expert, Spergel’s sense is that “it’s relatively rare that this happens.” He doesn’t think parents with children who are outgrowing an allergy should be unduly concerned. “But if all of a sudden three years later, the kid’s complaining of belly pains every day, take it seriously.” If routine conditions such as viruses are ruled out, a physician can then “realize that ‘this child had hives to milk three years ago and now he’s having a lot of milk’ – it might be a shortcut to get him better faster,” Spergel said.
While the CHOP study focused on children outgrowing a food allergy, there have also been studies of children who hve successfully undergone oral immunotherapy (OIT) for a food allergy later developing EoE. At the news conference, Dr. Wesley Burks of the University of North Carolina School of Medicine, says this is estimated to occur in 10 to 15 percent of OIT patients.
“One of the questions we have is whether or not these people had EoE before,” said Dr. Hugh Sampson, director of the food allergy institute at Mount Sinai’s School of Medicine in New York, who like Burks, is a leading OIT researcher. “Because they also had IgE-mediated food allergy, and weren’t getting the food, they didn’t have the demonstration of EoE.”
Spergel agreed, suggesting: “I think these kids probably always had EoE to the food but they weren’t eating it” since they were allergic to it. With OIT, “I don’t think we caused it (EoE), we uncovered it.”
Spergel finds the CHOP study helpful to the process of identifying foods that trigger EoE. He notes that when a physician sees a patient with esophagitis symptoms now, one of the key questions the doctor can ask is whether a food allergy has been outgrown.