Systemic quinine photosensitivity.

A 72-year-old woman developed a photodistributed skin eruption while taking quinine hydrochloride (250 mg) once or twice weekly for recumbency cramps. The histopathology showed an eczematous reaction. Phototesting after quinine therapy had been discontinued for one month revealed normal erythema thresholds for ultraviolet (UV) light in the A range (17 J/cm2) and UV light in the B range (20 mJ/cm2). A second phototest after a ten-day period of reexposure to quinine hydrochloride (250 mg daily) showed a drastically lowered threshold for UV light in the A range (less than 1.0 J/cm2), while the test for UV light in the B range was unchanged. The patient's dermatitis also exacerbated with pronounced itching. The histopathologic results from a positive test site were similar to those of her eczematous lesions. We believe this to be the first documented case of systemic quinine photosensitivity. The clinical picture, the results of the phototests, and the histopathology suggest a photoallergic mechanism.