The role of food and aeroallergens in eosinophilic oesophagitis

Eosinophilic oesophagitis (EoE) is a chronic inflammatory condition that afflicts children and adults, and causes oesophageal narrowing and fibrosis, with the resultant clinical sequelae of dysphagia and food bolus obstruction events (FBOE), the latter often resulting is hospitalisation, emergency endoscopic removal and rarely but catastrophically oesophageal perforation. An increasing number of patients are being diagnosed with EoE, and this is independent of a growing awareness of this recently defined condition, but rather represents a true increase in the context of a global rise (in Western first-world countries) of allergic conditions per se. The mainstays of medical treatment for EoE are indefinite PPI therapy or swallowed topical corticosteroids. These therapeutic assets are highly effective but they do not ultimately target the etiologic cause of EoE. A role for aeroallergens (pollens) and dietary allergens (food) in precipitating or causing EoE has been suggested in a number of studies, albeit limited by their retrospective nature and lack of control group (in the case of aeroallergens), the predominance of paediatric literature and variable use of adjunctive treatment such as proton pump inhibitors (PPIs) (in the case of food allergens). Highly restrictive elimination diets show promise in treating EoE. Unfortunately, the role of allergy tests in directing dietary therapy remains debatable and studies are again of a retrospective nature or utilise a small range of available tests. This means that even if dietary therapy works, that patients are required to undergo many gastroscopies during their treatment course, which is both inconvenient, expensive and has the associated risk of an anaesthetic. Thus, the need both to better understand the role of food and aeroallergens (with more comprehensive prospective studies), and to offer less invasive and thereby safer endoscopic surveillance is readily apparent.