Intestinal tuberculosis, Crohn's disease and ulcerative colitis in an urban black population.

The clinical, epidemiological and pathological manifestations of intestinal tuberculosis, Crohn's disease and ulcerative colitis in the Johannesburg Black population are reviewed. Crohn's disease and particularly ulcerative colitis have emerged as definite disease entities in urban Blacks. There is an evident similarity between the clinical manifestations of intestinal tuberculosis and of Crohn's disease, and also between those of Crohn's disease and ulcerative colitis. Furthermore the data suggest that genetic and environmental factors play a vital role in susceptibility to these diseases. The similarity between the clinicopathological manifestations of intestinal tuberculosis and those of Crohn's disease lends support to the view that microbial, viral or cellular toxic agents are involved in the aetiology of Crohn's disease. Moreover, the clinical and epidemiological features of ulcerative colitis support the concept that environmental factors present in an urbanized milieu are important in its aetiology.