Eosinophilic gastrointestinal diseases - Pathogenesis, diagnosis, and treatment

Eosinophilic gastrointestinal diseases (EGIDs) are divided into eosinophilic esophagitis (EoE) and eosinophilic gastroenteritis (EGE), depending on the involved gastrointestinal tract, though both are considered to be chronic Th2-type allergic diseases caused by food or environmental allergens. In development of EoE, refluxed gastric acid may also have an important role. For diagnosis of EGIDs, the presence of symptoms possibly originating from the involved gastrointestinal tract and dense eosinophil infiltration are important factors. Imaging studies, including endoscopy and computed tomography, along with histopathological examinations of biopsy specimens are useful for diagnosis, whereas laboratory testing of blood, urine, and stool samples has limited value. Three useful options for treating EoE patients are acid inhibitors, swallowed topical corticosteroids, and an elimination diet, while systemic administration of glucocorticoids is the standard treatment of EGE, though information is limited. Since the prevalence of EGIDs is increasing in Western countries as well as Japan, development of effective treatments based on sufficient evidence is becoming an urgent need.