Sarcoidosis in Johannesburg--a comparative study of black and white patients.

Fifty-one black and 31 white patients with histologically proven sarcoidosis were managed in the respiratory units of the Johannesburg and Hillbrow Hospitals between January 1965 and October 1987. A number of differences in the demographic, clinical and laboratory features of the disease were documented in the two groups. While none of the black patients presented with erythema nodosum, direct skin involvement was significantly more common (P less than 0.05), occurring in 59% of these patients. The mean serum angiotensin-converting enzyme level was raised in both groups, but hypercalcaemia occurred infrequently in black patients. Almost 60% of the patients received corticosteroids, and the clinical and objective response to therapy was not significantly different in the two groups. Before referral the diagnosis was often labelled tuberculosis in the black patients who had frequently received antituberculosis chemotherapy. The tuberculin skin test is helpful, since it was negative in all but 2 black patients with sarcoidosis.