Food allergy testing in eosinophilic esophagitis: what the gastroenterologist needs to know.

Eosinophilic esophagitis (EoE) is a clinicopathologic disease of increasing prevalence in children and adults. The triggering antigen in EoE is often a food that initiates a cascade of Th2-associated interleukins such as interleukin-5 and interleukin-13 and chemokines such as eotaxin-3 as well as esophageal eosinophilia and mastocytosis. Amino acid-based formulas have high efficacy rates in EoE and constitute the first evidence for food-triggered esophageal eosinophilia. Animal models have demonstrated the sufficiency of food antigens in triggering both the inflammatory and remodeling complications of EoE. Food elimination diets that are followed by single food introduction with repeat biopsy have proven the efficacy of empiric and allergy testing based elimination diets in children and adults. Although the ideal allergy test for identifying food antigens in EoE remains to be elucidated, the utility of food skin prick combined with atopy patch testing has been shown in large pediatric cohorts. By comparison, smaller, non-U.S. adult cohorts have not had similar results. Currently, a positive test on food allergy evaluation suggests a food trigger for EoE but does not substitute for biopsy-based tissue evaluation after food removal and reintroduction. The higher rates of food anaphylaxis in children with EoE, potential loss of tolerance to immunoglobulin E-positive foods that can occur with food avoidance, and the high rates of other atopic diatheses in EoE subjects all support the evaluation of EoE subject by an allergist, consideration for allergy testing, and an integrated approach by allergists, gastroenterologists, and pathologists in EoE management.