To the Editor.—
Those readers who may have been inspired by the two recent articles on polymorphous light eruption (PMLE)1,2 may find the points identified in the following case helpful when considering photo testing to confirm the diagnosis of PMLE. A number of standard dermatology texts indicate that the experimental reproduction PMLE is best done by administering repeated courses of ultraviolet B (UV-B) irradiation at several times the minimal erythema dose.3,4 The need to induce a phototoxic event to experimentally reproduce an eruption that occurs naturally without phototoxic levels of irradiation suggests that additional factors may need to be considered when photo testing is planned. We recently saw a patient who demonstrates this point very clearly.
Report of a Case.—
A 44-year-old truck driver was seen with a history of a pruritic papular eruption involving the neck, forearms, legs, and back that typically began approximately eight hours after
Marsh TW, Rietschel RL. Importance of Appropriate Wavelength, Dosage, and Test Site in the Experimental Reproduction of Polymorphous Light Eruption. Arch Dermatol. 1985;121(5):587. doi:10.1001/archderm.1985.01660050035003