Comparison of 755‐nm picosecond alexandrite laser versus 1064‐nm Q‐switched Nd:YAG laser for melasma: A randomized, split‐face controlled, 2‐year follow‐up study

Abstract Objectives Pulsed laser treatment of melasma has shown some promising results. To compare the effectiveness and safety of 755‐nm picosecond alexandrite laser (PSAL) fitted with diffractive lens array (DLA) versus 1064‐nm Q‐switched neodynimum:yttrium aluminum garnet laser (QSNYL) for the treatment of melasma. Methods We conducted a randomized, split face controlled, 2‐year follow‐up study. Each face was divided into two parts, each side receiving three treatments with either PSAL or QSNYL at 1 month intervals. Modified Melasma Area Severity Index scores (mMASI), pain scores, patient satisfaction and adverse events were recorded. In vivo reflectance confocal microscopy (RCM) images were acquired. Results Twenty subjects were enrolled and three dropped out. At 6 months, mMASI scores were significantly lower than baseline for QSNYL sides ( p = 0.022), with no statistically significant difference between PSAL sides before and after treatment, PSAL sides versus QSNYL sides, or patient satisfaction scores. QSNYL treatment was associated with less pain ( p = 0.014). No serious adverse events were reported. In the PSAL sides RCM showed a large number of dendritic melanocytes infiltrated in the dermis at 2 weeks and 4 weeks after treatment. Ten patients (58.82%) reported recurrence or exacerbation at 2‐year follow‐up with no statistically significant difference between the two lasers. Conclusions QSNYL demonstrated short term clinical efficacy for melasma, but did not provide any additional benefit compared to PSAL with DLA. QSNYL was associated with less pain. There was a high recurrence rate at 2‐year follow‐up. RCM allowed the detection of cellular changes in melasma lesions.