Clinical Review

American Journal of Gastroenterology (2002) 97, 794–802; doi:10.1111/j.1572-0241.2002.05595.x

Microscopic colitis: a review

Darrell S Pardi MD1, Thomas C Smyrk MD2, William J Tremaine MD1 and William J Sandborn MD1

  1. 1Division of Gastroenterology and Hepatology, Mayo Clinic and Foundation, Rochester, Minnesota, USA
  2. 2Department of Laboratory Medicine and Pathology, Mayo Clinic and Foundation, Rochester, Minnesota, USA

Correspondence: Darrell S Pardi, MD, 200 First Street Southwest, Rochester, MN 55905 USA.

Received 11 June 2001; Accepted 12 October 2001.



Microscopic colitis is a relatively common cause of chronic watery diarrhea, often accompanied by abdominal pain and weight loss. The colonic mucosa appears normal grossly, and the diagnosis is made when there is an intraepithelial lymphocytosis and a mixed inflammatory infiltrate in the lamina propria. The two main subtypes, collagenous and lymphocytic colitis, are similar clinically and histologically, distinguished by the presence or absence of a thickened subepithelial collagen band. Many potential pathophysiological mechanisms have been described, although none have been conclusively proved. There is a paucity of randomized treatment trials in these patients, although a rational approach to therapy often leads to satisfactory control of symptoms.