Eosinophilic Gastrointestinal Diseases: The Pathogenesis, Diagnosis, and Treatment

Eosinophilic gastrointestinal diseases are delayed-type chronic allergic disorders that show gastrointestinal eosinophil dense infiltration, with an exaggerated Th2-type immune reaction considered to be an important mechanism. These diseases can be roughly divided into two types: eosinophilic esophagitis, mainly found in young and middle-aged men, and eosinophilic gastroenteritis, which is found in both genders equally. A diagnosis of eosinophilic esophagitis is suspected when characteristic endoscopic findings, including longitudinal furrows and rings, are noted. However, characteristic endoscopic abnormalities are rarely found in cases with eosinophilic gastroenteritis, so multiple biopsy sampling from the apparently normal gastrointestinal mucosal surface is important for making an accurate diagnosis. The administration of systemic glucocorticoid is the standard treatment for eosinophilic gastroenteritis, while acid inhibitors and topical glucocorticoid swallowing therapy are effective for eosinophilic esophagitis. Anti-cytokine therapies for eosinophilic gastrointestinal diseases are currently under development.