Rue the herb: Ruta graveolens--associated phytophototoxicity.

We describe an unusual case of phytophototoxicity induced by an herbal plant, Ruta graveolens, from the Rutaceae family. This common herb, also called rue, can be found throughout rural settings in the United States. When psoralens from rue come in contact with human skin that is subsequently exposed to ultraviolet A light, an impressive photoirritant reaction can occur. This report both clarifies the distinguishing features of photoirritant reactions versus photoallergic reactions and reviews the pathophysiology and clinical presentation of phytophotodermatitis. R. graveolens can be associated with an impressive photoirritant reaction and should not be used as an insect repellent.