Microscopic colitis is an inflammation of the large intestine (colon) that causes persistent watery diarrhea. The disorder gets its name from the fact that it's necessary to examine colon tissue under a microscope to identify it, since the tissue may appear normal with colonoscopy or flexible sigmoidoscopy.

There are two subtypes of microscopic colitis:

  • Collagenous colitis, in which a thick layer of protein (collagen) develops in colon tissue
  • Lymphocytic colitis, in which white blood cells (lymphocytes) increase in colon tissue

Researchers believe collagenous (kuh-LAYJ-uh-nus) colitis and lymphocytic colitis may be different phases of the same condition. Symptoms, testing and treatment are the same for both subtypes.

The symptoms of microscopic colitis can come and go frequently. Sometimes the symptoms resolve on their own. If not, your doctor can suggest a number of effective medications.

Microscopic colitis care at Mayo Clinic

March 03, 2016
  1. Feldman M, et al. Other diseases of the colon and rectum. In: Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. 10th ed. Philadelphia, Pa.: Saunders Elsevier; 2016. http://www.clinicalkey.com. Accessed Jan.6, 2016.
  2. Microscopic colitis: Collagenous colitis and lymphocytic colitis. National Institute for Diabetes and Digestive and Kidney Diseases. http://www.niddk.nih.gov/health-information/health-topics/digestive-diseases/microscopic-colitis/Pages/facts.aspx. Accessed Jan.6, 2016.
  3. Dietrich CF. Lymphocytic and collagenous colitis (microscopic colitis): Clinical manifestations, diagnosis, and management. http://www.uptodate.com/home. Accessed Jan. 6, 2016.
  4. Pardi DS. Microscopic colitis. Clinics in Geriatric Medicine. 2014;30:5.
  5. Nguyen GC, et al. American Gastroenterological Association Institute guideline on the medical management of microscopic colitis. Gastroenterology. 2016;150:242.
  6. Münch A, et al. Microscopic colitis: Clinical and pathologic perspectives. Clinical Gastroenterology and Hepatology. 2015;13:228.
  7. Ohlsson B. New insights and challenges in microscopic colitis. Therapeutic Advances in Gastroenterology. 2015;8:37.
  8. Nutrition therapy for diarrhea. Nutrition Care Manual. Academy of Nutrition and Dietetics. https://www.nutritioncaremanual.org/client_ed.cfm?ncm_client_ed_id=20. Accessed Jan. 7, 2016.
  9. McNally PR. Colitis: Pseudomembranous, microscopic and radiation. In: GI/Liver Secrets Plus. 5th ed. Philadelphia, Pa.: Saunders Elsevier; 2015. https:// www.clinicalkey.com. Accessed Jan. 8, 2016.
  10. U.S. News best hospitals 2015-2016. U.S. News & World Report. http://health.usnews.com/best-hospitals/rankings/gastroenterology-and-gi-surgery. Accessed Dec. 27, 2015.
  11. Picco MF (expert opinion). Mayo Clinic, Jacksonville, Fla. Jan. 10, 2016.