Treatment outcome and persistence of repigmentation from narrow-band ultraviolet B phototherapy in vitiligo.

: Narrow-band ultraviolet B (NB-UVB) phototherapy is a mainstay treatment in vitiligo. However, data relative to repigmentation outcome, prognostic factors, and duration of repigmentation are limited. : To investigate the quantitative repigmentation outcome of NB-UVB phototherapy in vitiligo, the factors associated with favorable prognosis after NB-UVB, and the duration of repigmentation after NB-UVB discontinuation. Medical records of vitiligo patients who underwent NB-UVB phototherapy at Department of Dermatology, Siriraj Hospital during 2012 to 2016 were retrospectively reviewed. Repigmentation was assessed using Vitiligo Area Scoring Index (VASI) score. Fifty-eight patients were included. All patients received NB-UVB phototherapy twice to three times weekly for a median duration of 12 months. Forty-two patients had nonsegmental vitiligo (NSV), and 16 had segmental vitiligo (SV). NSV and SV demonstrated overall improvement in VASI score of -50.0%±31.0% and -40.0%±28.3%, respectively. Factors predictive of good outcome included type of vitiligo, lesion location, disease duration before NB-UVB, and duration and total number of NB-UVB treatments. Persistence of repigmentation was observed in approximately 80% of cases at one year after discontinuation of NB-UVB. NB-UVB phototherapy is an effective treatment for vitiligo, especially NSV. Repigmentation persisted in 80% of patients at 1 year after cessation of phototherapy.