Nature with Nurture: the Role of Intrinsic Genetic and Extrinsic Environmental Factors on Eosinophilic Esophagitis

Purpose of Review As the rising prevalence and incidence of eosinophilic esophagitis (EoE) has quickly outpaced the rate of esophageal biopsies, particularly in Westernized countries, several studies have suggested a link between intrinsic genetic and extrinsic environmental risk factors and the development, presentation, and diagnosis of EoE. This review aims to critically assess existing studies describing the role of the environment on the development, symptomatic presentation, and diagnosis of this recently recognized chronic immune-mediated disease. Recent Findings We present and critically evaluate the working hypotheses and supportive studies thus far on environmental factors on EoE, describe sources of potential bias in diagnosis due to socioeconomic factors and thus undermining studies of EoE etiology, and highlight opportunities for future research. Summary As genetics alone do not explain the rapid rise of EoE, we must look to environmental, or extrinsic, factors both in the early-life period which shape the development of the gut microbiome, as well as later life contributing to diagnosis of this new disease. Future etiologic studies linking risk factors to EoE development in individual patients are needed.