Eosinophilic gastroenteritis is rare in pediatric patients. The three main manifestations, defined by Klein et al. in 1970, were (a) predominant mucosal, (b) predominant muscular-layer, and (c) predominant subserosal disease. The predominant subserosal type is the rarest of the three. We report on a 43-month-old boy who, on admission, suffered from recurrent abdominal pain, vomiting and diarrhea for one week, with ascites and pleural effusion noted. The white blood cell (WBC) count of ascites fluid was 8,000/mm3, with a differential count of 99% eosinophils. The peripheral WBC count was 44,000/mm3, with 78% eosinophils. Three days after diagnosis, ascites, pleural effusion and other gastrointestinal symptoms were gradually relieved using steroid therapy, with the peripheral eosinophil count returning to normal. The steroid therapy was discontinued after two months with tapering dose. The boy was in good health with no recurrence of symptoms in a follow-up conducted after one year.
