|Classification and external resources|
Collagenous colitis is an inflammatory colonic disease with peak incidence in the 5th decade of life, affecting women more than men. Its clinical presentation involves watery diarrhea, usually in the absence of rectal bleeding. It is often classified under the umbrella entity microscopic colitis, along with a related condition, lymphocytic colitis.
On colonoscopy, the mucosa of the colon typically looks normal, but biopsies of affected tissue usually show deposition of collagen in the lamina propria, which is the area of connective tissue between colonic glands. Radiological tests, such as a barium enema are typically normal.
The exact cause of collagenous colitis is unknown, but non-steroidals such as diclofenac are commonly implicated. The other group of agents most commonly associated with collagenous colitis are the selective serotonin reuptake inhibitors used in the treatment of depression.
Treatment of collagenous colitis is often challenging, and many agents have been used therapeutically:
An association between collagenous colitis and celiac disease has been reported, but there is no evidence that dietary restrictions used in celiac disease management are of benefit in collagenous colitis therapy.
There have also been reports of an association between collagenous colitis and lymphoma.