Clinical characteristics of collagenous and lymphocytic colitis

Microscopic colitides (MC), collagenous colitis (CC) and lymphocytic colitis (LC) share clinical features, but their mutual relationship is unclear, and clinical comparative studies are rare. We aimed to examine the clinical features in CC and LC by focusing on concomitant diseases.Patients with MC (30 with CC, 54 with LC) were identified in the pathology databases and by reviewing biopsies. Controls included 84 age- and sex-matched persons. The clinical data collected from patient records were prospectively completed by interviews.The female:male ratio was 2:1 in CC and 5.75:1 in LC. Mean age at diagnosis was 53 in CC and 55.4 years in LC. There were no differences in the pattern of symptoms. Concomitant autoimmune diseases were more common in CC (53.3%) than in LC (25.9%; P = 0.017). Celiac disease was common in both CC (20%) and LC (14.8%). Bronchial asthma was associated with LC (25.9%), but not with CC (6.7%; P = 0.042). Colon diverticulosis was rare in MC (16%) compared with the controls (39%; P = 0.001). Hypolactasia was common in MC (45%; 76% in CC, 54% in LC) compared to its prevalence in the Finnish general population (17%).CC and LC are largely similar clinically, but the differences in the occurrence of autoimmune conditions and bronchial asthma suggest that they differ in immunopathogenesis. MC is associated with reduced lactose tolerance and shows a negative association with diverticular disease, possibly related to the small intestinal pathology and abnormal stool consistency.