BACKGROUND Several skin diseases are associated with human immunodeficiency virus (HIV) infection. In Africa, due to the difficult access to medical care and complementary examinations, certain diseases are of particular importance. In the present work, we report the skin manifestations observed in a dermatology unit of a large city in Africa over a 3 year period and which were the revealing signs of HIV infection. METHODS All adult subjects (>15 years) with a positive HIV serology (confirmed by Western blot) that had been revealed by a skin disease seen at the Marchoux Institute at Bamako between June 1991 and September 1994 were included in the study. RESULTS Two hundred sixty-three skin diseases revealed 233 cases of HIV infection. Diseases observed were: zoster (n = 71), seborrheic dermatitis (n = 43), Kaposi's sarcoma (n = 34), prurigo (n = 31), sexually transmitted diseases (n = 27), extensive dermatophytosis (n = 12), psoriasis (n = 12), molluscum contagiosum (n = 8), acquired ichthyosis (n = 3), cutaneous leishmaniasis (n = 2) and other skin diseases (n = 10). More than one disease were associated in 28 patients. Certain particular features were noted (superinfection of zoster, papular margin in dermatophytosis). CONCLUSIONS In Africa, certain skin diseases often reveal HIV infection and some diseases have a high positive predictive value for HIV infection (zoster, seborrheic dermatitis, prurigo, Kaposi's sarcoma, extensive dermatophytotis). For prognosis, frequently associated diseases are signs of AIDS (Kaposi's disease, prurigo, molluscum contagiosum).