Eosinophilic esophagitis (EoE) is a chronic, eosinophil-predominant inflammatory condition that can affect esophageal mucosa at any age. Distinguished from gastroesophageal reflux disease in the mid 1990's, it has seemed to be increasingly prevalent, and is usually a manifestation of food allergy. The endoscopic and histologic features are well described. The clinical manifestations vary considerably by age, with adolescents and adults complaining primarily of dysphagia. Younger children may present with pain, vomiting, other evidence for food allergy, or feeding difficulties. Treatment options include swallowed (non-systemic) steroids and dietary antigen elimination, and must be maintained indefinitely due to the extremely high rate of recurrence off therapy. The complications of untreated disease include fibrosis of the esophageal lamina propria and stricture formation that result in chronic dysphagia, risking food impaction and perforation.