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Medical Author:

Bhupinder Anand, MD

Medical Editor:

Jay W. Marks, MD

Jay W. Marks, MD

Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

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In this Article

• What is colitis?
• What diseases are not colitis?
• What is microscopic colitis?
• What causes microscopic colitis?
• What are the symptoms of microscopic colitis?
• How common is microscopic colitis and who is at risk?
• When should I seek medical care for microscopic colitis?
• How is microscopic colitis diagnosed?
• What is the treatment for microscopic colitis?
• What is the prognosis of microscopic colitis?
• Can microscopic colitis be prevented?
• Patient Comments: Microscopic Colitis - Symptoms
• Patient Comments: Microscopic Colitis - Treatments
• Patient Comments: Microscopic Colitis - Cause
• Find a local Gastroenterologist in your town
• Lymphocytic Colitis Index

A person should seek medical care if the diarrhea lasts for more than 2 weeks or is accompanied with symptoms such as weight loss, fatigue, and abdominal pain.

The diagnosis of microscopic colitis is made by performing biopsies from different regions of the colon during colonoscopy or sigmoidoscopy.

The abnormalities of the colon's lining in microscopic colitis occur in a patchy distribution (areas of normal lining may coexist adjacent to areas of abnormal lining). For this reason, multiple biopsies should be taken from several different regions of the colon in order to accurately make a diagnosis.

The patchy nature of microscopic colitis also is the reason why flexible sigmoidoscopy often is inadequate in diagnosing the condition because the abnormalities of microscopic colitis may be absent from the sigmoid colon (the colonic segment that is closest to the rectum and is within the reach of a sigmoidoscope) in 30% to 40% of the patients with microscopic colitis.

Thus, biopsies of other regions of the colon accessible only with colonoscopy may be necessary for diagnosing microscopic colitis.

The treatment of microscopic colitis has not been standardized because there have not been adequate large scale, prospective, placebo controlled treatment trials. The following strategies are safe and may relieve diarrhea in some patients:

• Avoid nonsteroidal antiinflammatory drugs (NSAIDs)
  
  
• Trial of lactose elimination (just to eliminate the possibility that intolerance to lactose in milk is aggravating the diarrhea)
  
  
• Antidiarrhea agents such as loperamide (Imodium) or diphenoxylate and atropine (Lomotil)
  
  
• Bismuth subsalicylate such as Pepto-Bismol
  
  
• budesonide (Entocort EC)
  
  
• 5-ASA (mesalamine) compounds such as Asacol, Pentasa, or Colazal

Controlled trials showed that budesonide (Entocort, a poorly absorbed steroid) is effective in controlling diarrhea in more than 75% of the patients with collagenous colitis, but the diarrhea tends to recur soon after stopping Entocort.

Though data supporting their use is lacking, some doctors may use medications that potently suppress the immune system such as azathioprine (Imuran, Azasan) and 6-mercaptopurine in patients with severe microscopic colitis that is unresponsive to other treatments.