[Eosinophilic esophagitis]

Eosinophilic esophagitis (EoE) was first described in the early 1990s. Initially a rarity, it is now the most common cause of dysphagia for solid foods in young adults. Its prevalence is estimated to be 1:2000. Mechanistically, EoE is characterized by a chronic type‑2 T‑helper cell (Th2) inflammation of the esophagus which is triggered by food allergens. It often occurs in association with other Th2-mediated diseases, such as asthma, atopic dermatitis, and chronic rhinosinusitis with nasal polyps. EoE is diagnosed based on an esophagogastroduodenoscopy with biopsies of the esophageal epithelium. The diagnosis can be established when both symptoms of esophageal dysfunction (usually dysphagia) and an eosinophilic infiltration of at least 15 eosinophils per high-power field (HPF) are present. EoE can be treated with drugs, diet, and endoscopic dilatation. In terms of diet, milk elimination appears most reasonable, particularly as first choice. Drug treatment includes proton pump inhibitors (PPI), topical steroids, and the biologic agent dupilumab. Endoscopic dilatation is effective but does not treat the underlying inflammation. Therefore, it should never be used alone, but rather as an add-on therapy. In cases where clinical suspicion of EoE is strong but no or only few eosinophils are detected in esophageal biopsies, the diagnosis of an EoE variant should be considered. This review article provides a detailed discussion of the epidemiology, clinical features, diagnosis, treatment, and variants of EoE.