Lupus erythematosus induced by medications, ultraviolet radiation, and other exogenous agents: a review, with special focus on the development of subacute cutaneous lupus erythematosus in a genetically predisposed individual.

Exogenous agents implicated in or suspected of precipitating subacute cutaneous lupus erythematosus (SCLE) and lupus erythematosus (LE) are reviewed. An illustrative case of environmentally induced SCLE is presented. A previously healthy 30-year male homozygous for the tumor necrosis factor-alpha (TNF-alpha) 308. A promoter allele developed SCLE after spending several hours removing fertilizer- and pesticide-containing hay from an agricultural barn in the springtime. The cutaneous eruption soon resolved, only to reappear 3 weeks later on the day the patient re-entered the barn. An environmental agent present in the barn, coupled with springtime ultraviolet light, likely triggered the disease in this immunogenetically susceptible individual.