A single‐blinded, randomized, controlled trial comparing efficacy between low‐fluence alexandrite 755‐nm picosecond laser and low‐fluence neodymium‐doped yttrium aluminum garnet (Nd:YAG) 1064‐nm picosecond laser for the treatment of ultraviolet B‐induced hyperpigmentation

Abstract Background Hyperpigmentation is a common concern of patients in dermatology clinics. Although there are many treatment options, lasers are considered a promising therapy for various hyperpigmentary conditions. Objectives This study aims to evaluate the efficacy of alexandrite 755‐nm picosecond and neodymium‐doped yttrium aluminum garnet (Nd:YAG) 1064‐nm picosecond lasers for the treatment of ultraviolet B (UVB)‐induced hyperpigmentation in Asians. Materials and Methods A randomized, single‐blinded study was conducted. UVB‐induced hyperpigmentation was performed in three spots by narrowband UVB. After 2 weeks, these three spots were allocated into 755‐treated, 1064‐treated, and control sites. Patients received weekly laser treatments for five sessions. Follow‐ups were scheduled at 1 and 2 months after the last session. Results Twenty patients attended the study. Overall, 755‐nm and 1064‐nm picosecond lasers showed a significant improvement in the mean lightness index ( L *) compared to the control site, which started at Day 49 and Day 77, respectively. The mean L * of the 755‐nm‐treated site was also higher than that of the 1064‐nm–treated site at Day 105 ( p ≤ 0.001). Initially, the mean L *, physician's visual analog scale (VAS), and patient satisfaction with the 1064‐nm picosecond laser were better than those with the 755‐nm picosecond laser. Nevertheless, an inversion of the mean L * and VAS was noted at Day 49, whereas the mean patient satisfaction was noted at Day 77. In the subgroup analysis, a 755‐nm picosecond laser effectively treated Fitzpatrick skin types (FPTs) III and IV. However, the mean L * of the 1064‐nm picosecond laser was not significantly different from that of the control for FPT4. Conclusion The alexandrite 755‐nm picosecond and Nd:YAG 1064‐nm picosecond lasers appear to be effective and safe modalities for treating UVB‐induced hyperpigmentation. With the setting employed in this study, the outcome after the 755‐nm picosecond laser treatment seemed superior to that of the 1064‐nm picosecond laser treatment, especially for FPT4.