Eosinophilic esophagitis (Eo E) is a chronic inflammatory condition characterized clinically by symptoms of esophageal dysfunction and histologically by dense eosinophilic infiltration. Its pathogenesis involves an immune-mediated response to environmental antigenic stimulation. The incidence and prevalence are increasing and Eo E has become the most common cause of dysphagia and food impaction in adults. Its management often requires a multi-disciplinary approach as treatment includes specialized diets, anti-eosinophilic medications and esophageal dilation once fibrostensosis has developed. This book discusses the causes, symptoms and treatment options of eosinophilia.