Microscopic colitis is a type of inflammatory bowel (colon) disease that causes persistent watery diarrhea. In order to identify the disorder, bowel tissue must be viewed under a microscope, as the tissue appears to be normal when examined during a colonoscopy or sigmoidoscopy.
There are three subtypes of microscopic colitis:
- Collagenous colitis: a layer of collagen grows in the bowel tissue
- Lymphocytic colitis: lymphocytes (white blood cells) multiply in bowel tissue
- Incomplete microscopic colitis: both features of collagenous and lymphocytic colitis are exhibited
Regardless of subtype, symptoms, testing and treatment remain the same.
Signs and symptoms include:
- Chronic watery diarrhea
- Cramps, bloating or abdominal pain
- Weight loss
- Fecal incontinence
Symptoms may come and go, and periodically resolve on their own.
Should You See a Doctor?
If symptoms last more than a few days, particularly watery diarrhea, contact your doctor so they can assess and, if needed, treat your condition.
It’s unclear what causes bowel inflammation. Possibilities include:
- Autoimmune diseases, such as celiac disease and rheumatoid arthritis, which attack the body’s healthy tissues
- Viruses that produce inflammation
- Bacteria that generate inflammation in the colon’s lining
- Medications that irritate the colon lining