Eosinophilic oesophagitis (EoE) is an allergic condition of the oesophagus. It is a clinico-pathological diagnosis in which intermittent dysphagia and/or food impaction in adults occurs in the presence of severe eosinophilic infiltration of the oesophagus. Symptoms can be less well defined in children, with feeding refusal, vomiting and failure to thrive. Patients tend to have a history of atopy, and both food and aero-allergens are implicated in EoE pathophysiology. EoE is defined as ≥15 eosinophils/high-power field in oesophageal biopsies.