Abstract
Microscopic colitis is 10.0 to 13.7% of patients with chronic watery diarrhea and 10.7 % of patients with irritable colon. The incidence of microscopic colitis is 8.6 / 100 000 / year (women: men - 4 : 1).
Collagenous colitis incidence is 5.5 / 100 000 / year (women: men - 20 : 1) and lymphocytic colitis 3.1 / 100 000 / year. Often with microscopic colitis occur in old age, at 6 to 7 decade, but they are also described in children.
The incidence in different regions of the world differ. But surely increase, because with awareness and accurate diagnosis of the frequency increases.