What is collagenous colitis?

Inflammatory disease: Microscopic colitis is an inflammation of the colon that causes persistent watery diarrhea. The disorder gets its name from the fact that one needs to examine colon tissue under a microscope to identify it. There are two varieties: collagenous colitis, in which a thick layer of protein/collagen develops in the tissue and lymphocytic colitis, in which white blood cells (lymphocytes) accumulate.

See below: It is a type of micoscopic colitis where instead of inflammatory cells being present, a layer of collagen is deposited in the tissue. It can cause diarrhea and is more common in women.