Eosinophilic esophagitis advances parallel the increased prevalence. Developments include refining the diagnostic criteria, identifying risk factors, appreciating the contribution of inflammatory pathways, recognizing the importance of subepithelial remodeling, validating trial endpoints, defining a role for biological therapies, and optimizing dietary therapy. Endoscopic outcomes have emerged as endpoints in trials of novel therapeutics. Expanding efforts seek to develop less-invasive methods to assess disease activity thereby reducing the burden of repeated endoscopic procedures during elimination diets. The functional lumen imaging probe is now identified as a determinant of complications with potential utility as a therapeutic endpoint.