Eosinophilic esophagitis (EE) is a rare disease characterized by esophageal symptoms and dense esophageal eosinophilic infiltrate, both of wich persist despite prolonged treatment with proton pump inhibitors. The pathogenesis is poorly understood, but there is an increasing body of clinical and basic evidence that EE is an immune-mediated disease triggered by both food and inhalant allergens. At present there is no consensus statement on the number of eosinophils requiredfor the diagnosis, but generally a number of 20 eosinophils per high power field is considered a significant cut-off point. Therapies considered to be effective in the treatment of EE include: specific elimination diets or elemental diets; either systemic or topical corticosteroids therapy; and therapy with a selective inhibitor of leukotriene D4 receptor.