Microscopic colitis is a type of inflammation of the colon, or large intestine, that can cause watery diarrhea and cramping. While it can be painful and unpleasant, it's much less severe than other types of inflammatory bowel disease.
It's called microscopic because the inflammation is too small to see with the naked eye. The only way your doctor can diagnose it is to take a sample of tissue and check it under a microscope.
There are two types of microscopic colitis:
The differences are minor and the symptoms and treatments are the same. However, the tissues of the two types of microscopic colitis look different under a microscope.
Watery (but not bloody) diarrhea that may last weeks to months
The symptoms may get better and then return.
To help diagnose microscopic colitis, your doctor may ask you to have a colonoscopy or sigmoidoscopy. Both procedures use a tube with a camera on it to inspect the colon.
During the procedure, your doctor collects tissue samples that will be checked for signs of microscopic colitis.
Microscopic Colitis Causes
Experts aren't sure what causes microscopic colitis, but bacteria, toxins, or viruses are possible causes. It could also be related to a problem with your immune system. Your body may react to a false threat and start attacking the cells in your own digestive tract.
Some medications can increase your risk for microscopic colitis, including: