Inhibition spectra of solar urticaria: a case report and a review of the Japanese cases.

A 34-year-old Japanese female with solar urticaria is described, who had an episode of urticarial response when she was exposed to indoor fluorescent light first and sunlight later. The action spectrum was found to range from 480 to 520 nm with an inhibition spectrum above 650 nm in the visible light by both postirradiation and preirradiation. Injection of in vitro-irradiated serum did not produce an urticarial wheal on the patient. In the Japanese literature, 17 cases of solar urticaria with inhibition spectra have been reported. The wavelength of the inhibition spectrum was longer than that of the action spectrum in each case.