ABSTRACT
Two months ago, a 9-year-old boy experienced intermittent abdominal pain regardless of food intake, without diarrhea, bloody stool, or nausea. Blood test results revealed a peripheral blood eosinophil count of 660 cells /µL, which was marginally elevated, without inflammatory reaction, occult blood, or enteric pathogens. The intestinal mucosa from the terminal ileum to the rectum was endoscopically normal, but mucosal biopsy revealed eosinophilic infiltration of the terminal ileum and whole colon with ≥20 eosinophils/high power field (HPF). Subsequent upper gastrointestinal endoscopy revealed normal endoscopic mucosa from the esophagus to the second part of the duodenum, but mucosal biopsy showed an eosinophil infiltration of ≥20 eosinophils/HPF. Based on the above findings, he was diagnosed with eosinophilic gastroenteritis (EGE). The cause of EGE and mechanisms of eosinophil infiltration have yet to be fully elucidated. For these nonspecific abdominal symptoms, evidence of eosinophilic infiltration of the gastrointestinal mucosa, specifically 20 eosinophils/HPF in each intestinal mucosa, is required for the definitive diagnosis of EGE. Even if only persistent abdominal pain develops, EGE diagnosis should be confirmed with the analysis of mucosal biopsy in addition to the review of allergic disease history and peripheral blood eosinophil counts.