Background Eosinophilic esophagitis (EoE) is a disease entity first described in the 1990s, but showing an increasing incidence that is characterized clinically by esophageal dysfunction and histologically by a striking eosinophil infiltration. Methods This article discusses new aspects of the pathogenesis, symptoms, diagnosis, and treatment of EoE. Results EoE affects both children and adults and is frequently associated with atopic disease and IgE sensitization. Barrier dysfunction and T‑helper 2 inflammation are considered to be pathogenetically important factors. Recently, a proton pump inhibitor (PPI)-sensitive EoE subtype as well as an EoE-like disorder have been described. Conclusion Research in recent years has contributed to a better understanding of the disease spectrum and pathogenesis of EoE, including genetic dispositions, thereby laying the foundation for innovative treatment approaches.