In recent years, Pneumocystis carinii pneumonia (PCP) has been increasingly reported in patients without human immunodeficiency virus (HIV) infection. The increased occurrence of PCP in non-HIV-immunocompromised subjects has been attributed to several factors: use of stronger immunosuppressive regimens, higher awareness of PCP, advanced diagnostic technology and nosocomial spread of P. carinii. Appearance of PCP subsequent to the use of immunosuppressive drugs has been noticed in many inflammatory diseases such as rheumatoid arthritis, systemic lupus erythematosus and ulcerative colitis. Dermatologists frequently use immunomodulating agents, but the occurrence of PCP in patients receiving immunosuppressive drugs for skin diseases is largely unknown. We report four cases where PCP appeared following the use of immunosuppressive drugs primarily for cutaneous diseases, namely pemphigus, cutaneous necrotizing vasculitis (two cases) and Behçet's syndrome. These cases were identified in a computerized database study (1979-95) to evaluate the occurrence of PCP among immunocompromised hosts without HIV infection.