There is no doubt that EoE is a disease of multifactorial etiology, but it is also known that there is a clear genetically driven allergic component, as not only eosinophilic infiltration but also the presence of TH2 cells, interleukin-5 (IL-5), IL-13, and eotaxin-3 have been identified in biopsies, implying that, in at least a segment of patients, the etiology of inflammation is allergic [1,7]. This evidence concerns the gene CCL26 and eosinophilic esophagitis.