Background: Recently the beneficial effect of excimer laser treatment has been reported for patients with vitiligo. The influence of treatment frequency on this effect is not clear.
Objectives: To determine the optimal frequency of 308-nm excimer laser therapy for vitiligo.
Methods: In this prospective, university-based hospital study over 12 weeks we enrolled 14 patients. Each had at least three stable vitiligo lesions in the same body area. The three stable vitiligo lesions in each subject were randomly assigned to receive excimer laser treatment once (1 x), twice (2 x) and three times (3 x) weekly, respectively. The initial ultraviolet (UV) dose was 50 mJ cm(-2) less than the 308-nm minimal erythematous dose in vitiligo skin. The UV dose was increased at each treatment session according to the erythematous response to the previous treatment.
Results: Thirteen subjects were treated for at least 6 weeks; seven were treated for all 12 weeks. At 6 weeks, the repigmentation rates for treated lesions were 8% (1/13) after 1 x weekly treatment, 23% (3/13) after 2 x weekly treatment and 62% (8/13) after 3 x weekly treatment (P = 0.0134; 3 x vs. 1 x weekly); at 12 weeks, these rates were 46% (6/13), 62% (8/13) and 69% (9/13), respectively (P = NS; 3 x vs. 1 x weekly). Repigmentation initiation correlated with treatment number, regardless of frequency (P = NS). As shown by Kaplan-Meier analysis, repigmentation occurred earliest in the most frequently treated lesions (P = 0.0336). At 12 weeks, the projected repigmentation rates for 1 x, 2 x and 3 x weekly treatment approached each other (60%, 79% and 82%, respectively); the mean repigmentation grades (on a scale of 0-5) for 1 x, 2 x and 3 x weekly treatment were 1.7, 2.4 and 3.3, respectively (P = 0.018; 3 x vs. 1 x weekly). Laser-induced repigmentation persisted in most cases over the entire follow-up of 12 months after the end of treatment.
Conclusions: 308-nm excimer laser therapy is effective against vitiligo. Although repigmentation occurs fastest with 3 x weekly treatment, the ultimate repigmentation initiation seems to depend entirely on the total number of treatments, not their frequency. However, treatment periods of more than 12 weeks may be necessary to obtain a satisfactory clinical repigmentation, particularly when vitiligo lesions are treated only 1 x or 2 x compared with 3 x weekly.