Eosinophilic esophagitis (EE) is a chronic inflammatory, immunoallergic disease of the esophagus that represents the most common eosinophilic gut disease. Understanding and diagnosis regarding this condition have greatly increased in recent years, particularly in Europe and North America, in parallel with other allergic disorders. It consists of dense esophageal infiltration with eosinophils in the absence of gastro-esophageal reflux (GER). It involves individuals at all ages, and is particularly common in males during childhood and up to the 5th decade of life. It manifests with chronic, intermittent esophageal symptoms that predominantly include dysphagia, food impaction episodes, and GER-attributable complaints that do not respond to antisecretory therapy. Endoscopically, EE is a polymorphous disease that presents with various changes in esophageal caliber, and subtle changes in mucosal appearance, which lead to biopsy collection as a key procedure for diagnosis. Management must be multidisciplinary, including gastroenterologists, pathologists, allergologists, and also nutrition specialists in pediatric cases. Regarding therapy, dietary food restrictions are especially useful in the management of pediatric EE, but effectiveness is lower in the adult, maybe because of a greater involvement of air allergens. Drug use is standard, particularly involving topical steroids, which may revert manifestations and histological lesions, even though recurrence following discontinuation is common.