Fixed solar urticaria to visible light successfully treated with fexofenadine

Fixed solar urticaria (FSU) represents an uncommon form of urticaria relate d mostly to radiation from the ultraviolet (UVB, UVA) and visible spectrum. The exact pathomechanism has so far remained unknown. A 52-year-old woman with a 3-year history of urticated eruptions limited to certain skin areas is presented. Photobiological testing revealed positive reactions limited t o the visible light range, The induced lesions appeared only in originally affected skin sites. The particular distribution of whealing supports the c oncept of specific alteration of mast cells in well defined areas. The clin ical findings and the results of phototesting lead to the diagnosis of FSU to visible light, It is recommended to carry out phototesting in patients w ith FSU in the originally affected skin areas usually covered and protected by the patient, to avoid false-negative results. Fexofenadine given in the conventional dosage can prevent recurrences and represents a successful tr eatment measure when dealing with this peculiar form of solar urticaria.