A Guide to Microscopic Colitis

Medically Reviewed By Youssef (Joe) Soliman, MD
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Microscopic colitis is when atypical immune reactions cause inflammation in the colon. It is a less common type of inflammatory bowel disease (IBD).  Symptoms include abdominal pain, diarrhea, cramps, weight loss, and nausea.

Research suggests that older adults and people assigned female at birth may be at a higher risk of this condition. 

This article discusses microscopic colitis, including its symptoms, causes, and treatments.

Sex and gender exist on a spectrum. This article uses the terms “female” and/or “male” to refer to sex that was assigned at birth. 

Learn more about the difference between sex and gender here.

What is microscopic colitis?

a doctor is using a microscope
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Microscopic colitis is a type of inflammatory bowel disease (IBD) that doctors can only detect under a microscope. IBDs are chronic conditions characterized by inflammation in the intestines.

Generally, microscopic colitis is non-life-threatening. However, it can irritate the intestinal lining, causing frequent watery diarrhea and dehydration.

Many cases of microscopic colitis come and go and may intensify in response to certain triggers.


There are two subtypes of microscopic colitis. They include:

  • Collagenous colitis: This is when a thick layer of collagen bands in the lining of your colon. Collagen is a protein in your skin, tendon, bone, cartilage, and the connective tissue of your intestinal lining.
  • Lymphocytic colitis: This is when the number of lymphocytes multiplies unusually in the surface layer of the inner intestinal tract. Lymphocytes are a type of white blood cell that is part of the immune system.

The symptoms and treatments for these two subtypes are the same.

Learn about other types of colitis here.

Who gets microscopic colitis? 

Microscopic colitis can affect anyone. However, older adults and people assigned female at birth may be at a greater risk.

Additional possible risk factors include:

  • smoking 
  • having certain autoimmune diseases, such as celiac disease and psoriasis
  • having a family history of IBD
  • using certain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), statins, and proton pump inhibitors

Symptoms of microscopic colitis

The most common symptom of microscopic colitis is frequent watery diarrhea

Other symptoms include:

  • abdominal pain or cramps 
  • dehydration
  • weight loss
  • stool urgency
  • nausea and bloating
  • stool incontinence

These symptoms may relapse and return frequently. Sometimes, the symptoms disappear and never come back.

See your doctor if they persist.

Learn about other causes of watery diarrhea here.

Causes and triggers of microscopic colitis

Doctors do not know exactly why microscopic colitis occurs. However, they suspect that genetics and atypical immune reactions may play a role.

Other possible contributory factors include:

  • certain bacteria and bacterial toxins
  • inflammation-causing viruses
  • improperly absorbed bile acid

The following factors may also trigger symptoms: 

  • caffeine and alcohol 
  • gluten and dairy
  • sugar and artificial sweeteners

Treating microscopic colitis

Some home remedies may make symptoms of microscopic colitis go away. They include:

  • drinking lots of water
  • consuming more easy-to-digest foods, such as white rice, salmon, and banana
  • reducing your fiber intake
  • cooking vegetables properly before eating them
  • eating more small meals and fewer large meals
  • avoiding high sugar or high sorbitol drinks 
  • avoiding alcohol and caffeine
  • avoiding smoking
  • discontinuing use of possible trigger medications 

Your doctor may also recommend:

  • corticosteroids, such as budesonide (Pulmicort), to reduce inflammation
  • bulk-forming laxatives, such as psyllium (Metamucil), to make stool softer and easier to pass
  • immunosuppressants, such as TNF inhibitors (adalimumab, infliximab), to reduce atypical immune activity
  • anti-diarrheal medicines, such as loperamide (Imodium), to reduce the number of bowel movements and make your stool less watery

Diagnosing microscopic colitis

Your doctor will ask about your medical history and current medications to see if you have microscopic colitis. They may also conduct some lab tests to rule out other possible conditions. 

These tests may include:

  • Blood tests: This checks the types and numbers of cells in your blood. It can also help detect infection.
  • Stool tests: This analyzes a sample of your fecal matter for signs of viruses and harmful bacteria. Alternative names for the test include stool culture, fecal sample test, and stool sample test.
  • Imaging tests: This uses different forms of energy, such as X-rays and radio waves, to examine your abdomen or pelvis. Types include a CT scan, X-ray, and MRI.
  • Colonoscopy: This is when a doctor examines your colon with a long, camera-fitted tube. It can check for signs of inflammation and irritated tissues.
  • Biopsy: This is when your doctor takes a sample of your colon tissue for microscopic analysis. It can help rule out other IBDs.

Outlook for microscopic colitis

In many cases, microscopic colitis goes away with treatment. However, it may persist for months or even years.

For the best outcome, follow your doctor’s treatment plan.


Microscopic colitis is when atypical immune reactions cause inflammation in the colon. It can cause abdominal pain, cramps, weight loss, and nausea.

Doctors do not know the exact cause of the condition. However, they believe that bacteria, viruses, and certain medications may play a role. Other possible risk factors include aging, being female, and alcohol use.

You may be able to treat microscopic colitis at home. Try drinking lots of water and consuming more easy-to-digest foods. Also, try avoiding alcohol, caffeine, and high sugar drinks.

Be sure to seek medical treatment if your symptoms persist.

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Medical Reviewer: Youssef (Joe) Soliman, MD
Last Review Date: 2022 Aug 25
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