Eosinophilic Esophagitis: A Review of Histopathological and Diagnostic Aspects

Eosinophilic esophagitis (EoE) has emerged as a distinct clinicopathological entity and a major cause of upper gastrointestinal morbidity worldwide. Once misinterpreted as a variant of Gastroesophageal Reflux Disease (GERD), its unique identity as an immune-mediated inflammatory disease was solidified by foundational studies in the early 1990s. This discursive review synthesizes key findings from peer-reviewed literature to outline the evolution of EoE's diagnosis and management. The review highlights that a definitive diagnosis is now a multidisciplinary process that integrates clinical symptoms, characteristic endoscopic findings, and, most critically, a comprehensive histopathological evaluation of esophageal biopsies. It emphasizes the limitations of relying on a single eosinophil count and underscores the value of ancillary histological features and the Histologic Scoring System, which provides a more nuanced and predictive assessment of disease activity. The review also discusses the evolving understanding of PPI-responsive esophageal eosinophilia as a subtype of EoE, streamlining the diagnostic approach. In conclusion, while EoE is a chronic condition that can lead to significant esophageal remodeling if untreated, a robust diagnostic framework and a range of effective therapies are now available to manage the disease, though a continued lack of clinical awareness remains a key challenge.