title: Collagenous colitis and eosinophilic gastritis in a 4-year old girl: a case report and review of the literature.
abstract: Collagenous colitis (CC), a form of microscopic colitis, is characterized by a thick subepithelial collagen layer in the colon in the presence of chronic nonbloody watery diarrhoea and macroscopically normal-appearing colonic mucosa. Typically affecting elderly adults, CC is rare in children with only 12 cases previously reported in the literature. We report the case of a 4-year-old girl with CC associated with eosinophilic gastritis, which was clinically responsive to treatment with ketotifen, a benzocycloheptathiophene derivative, and H(1) class of antihistamine that stabilizes mast cells and potentially impairs eosinophil migration to target organs. We review the published cases of paediatric-onset CC and summarize the links between eosinophils and CC in the clinical and basic science literature.
  
  
  CONCLUSIONS
  CC is a rare cause of chronic diarrhoea in children and may relate to mast cell and eosinophil activity.
authors: Division of Gastroenterology, Hepatology and Nutrition, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors: Eric I
authors: EI
authors: Benchimol
authors: Richard
authors: R
authors: Kirsch
authors: Sandra
authors: S
authors: Viero
authors: Anne M
authors: AM
authors: Griffiths
mesh_terms: D046729:Colitis, Collagenous / Q000453:epidemiology* / Q000473:pathology; D004384:Duodenoscopy; D004804:Eosinophils / Q000378:metabolism*; D004945:Esophagoscopy; D005260:Female; D005756:Gastritis / Q000453:epidemiology* / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007223:Infant; D008407:Mast Cells / Q000378:metabolism; D011706:Pyloric Antrum / Q000378:metabolism / Q000473:pathology