Randomized, evaluator‐blinded comparative study of a potassium titanyl phosphate (KTP) 532‐nm picosecond laser and an alexandrite 755‐nm picosecond laser for the treatment of solar lentigines in Asians

Abstract Background Various pigment‐specific lasers can be used to treat solar lentigines. However, the most effective treatment options remain to be explored to reduce complications, such as postinflammatory hyperpigmentation, especially in dark‐skinned patients. Objectives This study aims to compare the efficacy and safety between the KTP 532‐nm picosecond laser and the alexandrite 755‐nm picosecond laser for the treatment of solar lentigines in Asians. Materials and Methods Thirty patients who had at least two solar lentigines on their arms were enrolled. A total of 30 paired lentiginous lesions were randomly selected for a single treatment with either a KTP 532‐nm picosecond laser or an alexandrite 755‐nm picosecond laser. Mean luminance score (L*) was evaluated at baseline and at 6 and 12 weeks to determine treatment efficacy. Improvement was assessed by a blinded physician using a 5‐point score. Satisfaction was rated by patients using a visual analog scale. All adverse events were documented. Results All 30 patients completed the study. Both lasers showed significant improvement in mean L* from baseline ( p < 0.001). With the parameter settings employed, lesions treated with the alexandrite 755‐nm picosecond laser showed greater improvement in mean L* when compared with treatment with the KTP 532‐nm picosecond laser at 12 weeks follow‐up ( p = 0.002). According to physician scoring, more than 50% improvement was observed in 25 and 19 lesions of the alexandrite 755‐nm picosecond laser group and the KTP 532‐nm picosecond laser group, respectively. Adverse events did not differ between groups. A significantly higher satisfaction score was observed with the alexandrite 755‐nm picosecond laser at the last visit ( p = 0.038). Conclusion Both types of picosecond laser may be used to treat solar lentigines. Proper treatment settings and endpoint observation are the most important factor to achieve a successful outcome.