Eosinophilic Oesophagitis: Current Understanding and Future Directions

Abstract

Eosinophilic oesophagitis (EoE) is an emerging disorder that manifests clinically with characteristic symptoms of oesophageal dysfunction and histologically by tissue eosinophilia. This chronic immune-mediated oesophageal disease represents a response primarily to food antigens. The incidence of EoE is escalating in both adults and children. This rise stems not only from heightened recognition but also an increased frequency of allergic/atopic diseases and defective immune tolerance. In adults, EoE presents as intermittent solid-food dysphagia or food impaction, heartburn, and chest pain, typically presenting in young men with known allergies. Presentation differs in children, who experience upper gastrointestinal complaints: abdominal pain, vomiting, feeding difficulties, and/or failure to thrive. Endoscopic features include circular rings, linear furrows, white exudative plaques, strictures, and mucosal fragility. The pathologic hallmark of EoE is mucosal eosinophilia (>15 eosinophils per high-power field) isolated to the oesophagus. Such tissue eosinophilia must be distinguished from gastro-oesophageal acid reflux that responds to optimal proton pump inhibitor (PPI) treatment and from PPI-responsive oesophageal eosinophilia (PPI-ROE). Innovative modalities such as high resolution digitally-enhanced endoscopy and functional luminal impedance planimetry are emerging to better detect EoE and monitor its response to treatment. Current therapeutic strategies involve elimination and elemental diets to avoid food allergens, topical corticosteroids to counter the inflammatory response, and endoscopic dilation of fibrostenotic complications. Other treatments have employed immunosuppressants, antagonists to the leukotriene and T helper Type 2 inflammatory pathways, and biologics that target interleukins, tumour necrosis factor, or immunoglobulin E with variable success. This review highlights the current understanding of the epidemiology, pathogenesis, presentation, treatment, and natural history of EoE, and scrutinises current controversies and future directions for investigation.