Prolonged benefit following ultraviolet A phototherapy for solar urticaria.

Two patients with severe idiopathic solar urticaria, previously resistant to a variety of therapies including plasma exchange, benefited from springtime courses of ultraviolet A (UVA) monotherapy. Sites which are normally exposed to sunlight were treated, in a cabinet fitted with Philips R-UVA lamps (emitting UVA and visible wavelengths, with peak at 350 nm), twice daily for 2-3 weeks. One patient has been treated in this way for 3, and the other for 2, consecutive years. Repeat monochromator phototesting 3 months after their latest courses of UVA showed a persistent reduction in severity of abnormal photosensitivity. Both patients describe a sustained improvement in their condition lasting over 6 months after treatment.