[Collagen colitis and lymphocytic (microscopic) colitis: different or common origin?].

Collagenous and lymphocytic colitis are two chronic inflammatory colonic diseases characterized by chronic watery diarrhea. They can only be diagnosed by histological examination of colonic biopsies. The pathogenesis is unknown, but may be of an inflammatory possibly autoimmune nature. Others hypothesize that a bacterial toxin or another noxious luminal factor is responsible for the development of the microscopic colitis syndrome. Some studies suggest that NSAIDs may be an etiologic factor in collagenous colitis in a subgroup of patients with this disease. These disorders may be different entities, although some data support the possibility that they are only different manifestations of the same disease. Therapy with 5-aminosalicylate and in severe cases corticosteroids, is successful in most patients. The course of these chronic diseases is commonly benign and is characterized by periods of spontaneous remissions and relapses, but clinical and histopathological resolutions are occasionally seen. On the basis of our own two cases and the literature, these two diseases will be discussed. These patients were admitted to our hospital within a month of each other due to therapy-refractive chronic watery diarrhea. A 70-year-old woman had been suffering from diarrhea for more than ten years. The histological examination produced a diagnosis of collagenous colitis. Lymphocytic colitis was diagnosed from a histological examination in a 30-year-old man who had been suffering from diarrhea for six months. Both received a therapy of mesalazine and the symptoms disappeared within three weeks.