Eosinophilic oesophagitis.

Eosinophilic oesophagitis (EoE) is an antigen-driven pan-oesophagitis that is defined by the presence of at least 15 eosinophils per high power field on oesophageal histology in conjunction with upper gastrointestinal symptoms. EoE is closely associated with atopic disorders, in particular with food allergy, and as for other atopic diseases in childhood, there is a strong preponderance of male patients who have this disorder. The mechanisms leading to EoE have been characterised at the molecular level. Eotaxin-3, interleukin-5 and interleukin-13 are the key effector molecules in EoE pathogenesis. EoE presents with a diverse range of gastrointestinal symptoms, including regurgitation, vomiting, feeding difficulties or feeding refusal in infancy, as well as heartburn, dysphagia and food bolus impaction in older children and adults. The diagnosis may also be ascertained as an incidental finding in patients undergoing gastroscopy for other suspected conditions, including coeliac disease. EoE is different from gastro-oesophageal reflux disease and does not improve in response to proton pump inhibitors. Therefore, EoE needs to be distinguished from so-called PPI-responsive oesophageal eosinophilia. The long-term prognosis of EoE remains poorly defined, and complications mainly relate to subepithelial remodelling and fibrosis that may result in dysmotility, dysphagia and oesophageal strictures. The treatment of EoE involves elimination diets and topical swallowed aerosolised corticosteroids, while biological therapies targeting molecular mechanisms have so far been unsuccessful. In children, elemental diets have proved highly effective, but multiple food elimination diets are more sustainable in the long term. Further randomised, controlled trials on dietary or pharmacological interventions are needed to inform the optimal long-term management of EoE.