Targeted UVB phototherapy for psoriasis: a preliminary study.

Excimer laser treatment for psoriasis has been associated with good results at a lower cumulative dose than narrowband ultraviolet (UV)B protocols. To examine the clinical performance of a new targeted UVB lamp (290-320 nm; BClear) in the treatment of plaque-type psoriasis, 28 consecutive patients attending a dermatology service were treated twice weekly with the UVB lamp for 6-18 sessions (median 10). UV doses were based on multiples of a predetermined minimal erythema dose (MED). MEDs ranged from 150 to 350 mJ/cm2; maximal dose was 8 MED. Mean cumulative fluence until remission was 12.63 J/cm2. The Psoriasis Severity Index (PSI) was measured every 2 weeks for 16 weeks. Mean PSI improvement during treatment peaked at 73% after 6 weeks, and declined to 63% at 16 weeks. At that point, 36% of the patients had a > 75% improvement in PSI, and 21% showed complete clearance. Targeted radiation with the UVB lamp is effective for the treatment of plaque-type psoriasis, requiring as few as six sessions and achieving moderately long remission. As treatment is selectively directed toward lesioned skin, normal surrounding skin is spared unnecessary radiation exposure.