Rarely, as some children outgrow a food allergy, another may develop to the same food but in a stronger, more potentially dangerous way.

Healthcare providers and caregivers who carefully monitor children with food allergies may be able to recognize the early signs of eosinophilic esophagitis. This is a severe type of food allergy which has been increasing over the 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,” explained pediatric allergist Jonathan M. Spergel, M.D., Ph.D., of The Children’s Hospital of Philadelphia.

EoE often first seen in childhood

Only recently recognized as a separate and distinct allergic condition, the symptoms of EoE are swelling and inflammation of the esophagus with excessive levels of immune cells called eosinophils. It may be painful, cause weight loss, vomiting, heartburn and difficulty swallowing. It may develop at any age but is most often diagnosed in children who are showing failure to thrive.

An IgE-mediated food allergy is the more common variety of allergy. It occurs when antibodies have an exaggerated immune response to specific, harmless proteins in food. Nut, wheat, egg, and milk allergies commonly produce this reaction, which may cause hives, vomiting and other symptoms.

IgE may predispose a patient to EoE

Researchers took a look at 1,375 pediatric patients admitted to CHOP between 2000 and 2012. Of that number, 425 had definite food allergies most commonly to milk, egg, soy and wheat. Of those, 17 developed EoE to a food after having outgrown and IgE type 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,” noted 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.” He noted that 10 percent of patients who undergo desensitization therapy for food allergies eventually develop EoE to the same food. This needs to be considered and remembered as those therapies take place.