Photoallergic contact dermatitis to musk ambrette. Histopathologic features of photobiologic reactions observed in a persistent light reactor.

Studies concerning a patient with contact photosensitivity to musk ambrette, a commonly used fragrance, are reported. The patient had a persistent light reaction. The patient's history, clinical appearance, and phototest and photopatch test results are described. The observed patterns of these were identical to those previously noted in patients who had persistent light reactions after exposure to other photosensitizers such as the halogenated salicylanilides. The histopathologic findings in the phototest and photopatch test sites were those of an acute spongiotic dermatitis. No abnormal change was seen with ultraviolet A radiation exposure alone.