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.

There are two types 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

It isn't known whether collagenous (kuh-LAYJ-uh-nus) colitis and lymphocytic colitis are two separate disorders or represent different phases of the same condition. However, symptoms of collagenous colitis and lymphocytic colitis are similar, as are testing and treatment.

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.

Jan. 30, 2013