Ultraviolet phototherapy of uremic pruritus.

Repeated exposure to mid-range ultraviolet light (UVB) can dramatically relieve the pruritus associated with uremia. The efficacy of UVB phototherapy in uremic pruritus has been established in a controlled trial; experience with 38 patients suggests that 80 to 90% of those receiving 6 to 8 exposures respond favorably within the treatment period (2 to 5 weeks). Treatment frequency appears not to influence the remission rate, although patients on more intensive schedules experience relief sooner than those treated once weekly. Remissions are long-lasting in many patients, sometimes longer than 2 years. Patients with recurrent pruritus respond to phototherapy at least as well as previously untreated patients and tend to improve more rapidly. UVB phototherapy appears to exert its beneficial effect systemically rather than locally, but its mechanism of action is otherwise unknown.