Dermatology / HIV / Homosexuality / Humans / Alcoholism / Male / Sexual Behavior / Heroin Dependence / Skin Diseases / Clinical Sciences / Middle Aged / Human immunodeficiency virus / Pyrimethamine / Adult / Public health systems and services research / Combination drug therapy / Porphyrias / Chloroquine / Substance-Related Disorders / Male / Sexual Behavior / Heroin Dependence / Skin Diseases / Clinical Sciences / Middle Aged / Human immunodeficiency virus / Pyrimethamine / Adult / Public health systems and services research / Combination drug therapy / Porphyrias / Chloroquine / Substance-Related Disorders