The Role of Allergy Testing in Eosinophilic Esophagitis: an Update of the Evidence.

OPINION STATEMENT: Allergy testing has been advocated for patients with eosinophilic esophagitis (EoE) as a means of defining food triggers and directing dietary therapy. Several recent and comprehensive studies have demonstrated the futility of skin prick (SPT), skin patch (APT) and serum food antigen specific IgE (SIgE) estimates in this context. Furthermore, if identification of food triggers is the endpoint (as opposed to the ability of an allergy test-directed diet merely to induce remission), previous positive studies have limitations. Evolving evidence that EoE may be a non-IgE-mediated disease has led to trials of new assays including serum IgG to food allergens, the cytokine thymic stromal lymphopoietin (TSLP) and basophil activation, all without success. Rather than using allergy test-directed diets, the clinician should use empirical elimination diets which are practical, and consider minimally invasive sampling of the oesophagus to facilitate dietary reintroduction. Research should be redoubled to consider not only assays to predict food triggers but also those that monitor disease activity. The anti-inflammatory effect of proton pump inhibitors and deficits in barrier integrity may influence the success of dietary therapy and the results of allergy tests and should be considered in future research design.