PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: Not specified Endocrine therapy: No concurrent systemic steroids Radiotherapy: No prior x-ray therapy for acne No prior/concurrent ultraviolet light (PUVA or UVB) therapy for psoriasis Surgery: Not specified Other: No concurrent megavitamin or mineral supplementation At least 5 years since treatment with antimetabolites, folic acid inhibitors, alkalating agents, etc.