Solar urticaria: report of two cases with augmentation spectrum

Two adult Japanese patients with severe solar urticaria are reported. In both patients, an action spectrum existed in the visible light range, and an augmentation spectrum was demonstrated in the visible light range longer than the action spectrum. The augmentation phenomenon has rarely been documented, and in the previous reports, it was induced by preirradiation with the augmentation spectrum. In our cases, however, only postirradiation with the augmentation spectrum enhanced urticarial reactions.