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 532nm 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.

Wavelength‐dependent threshold fluences for melanosome disruption to evaluate the treatment of pigmented lesions with 532‐, 730‐, 755‐, 785‐, and 1064‐nm picosecond lasers

“…Table 4 summarizes the calculated and clinical irradiation parameters and their results for the treatment of epidermal and dermal lesions. For the 532‐nm picosecond laser, the incident fluence calculated for melanosomes located in the epidermis was mostly consistent with the clinical parameters A, 42 B, 43 and C 22 . The study C reported histological images of solar lentigines irradiated with a 532‐nm picosecond laser at a spot size of 4 mm and a fluence of 0.5 J/cm², which matched with the calculated irradiation parameters.…”

“…The results of the calculated incident fluences were consistent with irradiation parameters that achieved favorable clinical results for pigmented lesions treated with picosecond lasers in patients with Fitzpatrick skin types III or IV 21,22,42–49 . Table 4 summarizes the calculated and clinical irradiation parameters and their results for the treatment of epidermal and dermal lesions.…”

The Emerging Role of Visible Light in Melanocyte Biology and Skin Pigmentary Disorders: Friend or Foe?

“…QSRL and QSAL are considered the best choices as phototherapy for treating dermal pigmented lesions by Bogdan et al [102]. Yet the newly developed picosecond laser with higher efficiency in pigment removal and less thermal damage is worthy of consideration [138,139].…”

Efficacy of isobutylamido thiazolyl resorcinol for prevention of laser‐induced post‐inflammatory hyperpigmentation: A randomized, controlled trial

“…For topical treatment, various options including hydroquinone (HQ), tretinoin, adapalene, and chemical peeling were commonly used. 2 However, these treatments usually take longer period to achieve a clinical improvement compared to physical therapies such as Q-switched (QS) lasers (e.g., alexandrite, ruby, Nd: YAG), 4,5 picosecond laser, 6,7 intense pulsed light, 8 and cryotherapy. 2 For decades, a 532 nm QS Nd: YAG laser has been proved its efficacy in the treatment of SLs.…”