Eosinophilic esophagitis: New insights in pathogenesis and therapy.

Eosinophilic esophagitis (EoE) is a clinico-pathological entity with esophageal symptoms and dense esophageal eosinophilic infiltration throughout the esophagus that may persist despite treatment with proton pump inhibitors. This eosinophilic infiltration is usually absent in the stomach, small intestine and colon, although there are a number of reports of patients with a multi-organ involvement. EoE is associated with abnormalities involving TH2-dependent immunity, with multiple environmental factors strongly contributing to disease expression. The layer of the esophagus affected by the eosinophilic infiltration causes the specific symptoms. Esophageal involvement results mostly in dysphagia for solids that can be severe enough to cause recurrent esophageal obstruction with typical endoscopic features suggesting esophageal remodeling and pathological changes of eosinophilic infiltration of the mucosa, sub-epithelial fibrosis and muscle hypertrophy. This disease is frequently associated with other allergic conditions such as allergic asthma, allergic dermatitis and eosinophilia. The treatment of patients with EoE depends on the severity of the symptoms and of the inflammatory process as well as to their response to a gradual step-up treatment. The first line of treatment consists of steroid containing local inhalers. If unresponsive they are then treated with oral steroids. Intravenous interleukin blockers seem to have a consistent positive therapeutic effect.