[Collagen colitis--a clinical entity of relevance].

Collagenous colitis is a clinical and pathological entity characterized by chronic watery diarrhea and deposition of collagen beneath the surface epithelium of the large intestine. By colonoscopy and barium enema the colon appears normal. The laboratory tests give usually normal results. 75% of the patients are middle-aged women with a mean age around 50 years. The etiology of the disease is still unknown. An association with various autoimmune diseases has been suggested, but was never proven. Up to now, it is not clear whether the collagenous colitis is a distinct entity or only an epi-phenomenon of another disease which leads to thickening of the collagen layer. Collagenous colitis is diagnosed if all other diseases with chronic watery diarrhea are excluded. A specific treatment is not known. Symptomatic treatment with bulk and antidiarrheal drugs improves the symptoms of most of the patients.