Defining eosinophilic colitis in children: insights from a retrospective case series.

Objectives: Although it is a well-described syndrome in infants, eosinophilic colitis is a loosely defined and poorly understood diagnosis in older children. The aims of this case series were to characterise colonic eosinophilia in children and to determine whether it represents a distinct clinicopathological condition. Methods: We retrospectively reviewed symptomatic children older than 12 months with the principal diagnosis of colonic eosinophilia who presented between January 2000 and February 2007 (n = 38) and a further 10 children whose colonic biopsies were reported as histologically normal. The eosinophil density in all available gastrointestinal biopsies (n = 620) of these children was determined using a validated quantitative morphometric method. Patients were subdivided according to mean colonic eosinophil levels into 3 groups (marked, moderate, or minimal colonic eosinophilia). The following patient information was obtained and compared among patient groups: symptoms prompting endoscopy, atopic history, outcome, serum C-reactive protein and total immunoglobulin E (IgE) levels, erythrocyte sedimentation rate, blood eosinophil count, and endoscopic findings. Results: In all 3 patient groups, there was a colonic gradient of decreasing eosinophil density from caecum to rectum. Upper gastrointestinal tract biopsies did not exhibit eosinophilia. Although a significant association (P=0.03) between abnormal total IgE levels and moderate or severe colonic eosinophilia was found, there was no significant difference (P > 0.05) in other patient characteristics. Furthermore, follow-up data did not show a consistent relation between eosinophil density and progression of symptoms. Conclusions: We find no association between "eosinophilic colitis," defined as a histologically demonstrated marked colonic eosinophilia, and symptoms, history of atopy, inflammatory markers, or clinical outcome.