Evaluation of the safety and efficacy of the dual wavelength picosecond laser for the treatment of benign pigmented lesions in Asians

Abstract

Background and objectives: Cutaneous pigmentary disorders are both more common and more difficult to treat in patients with skin color given the higher melanin content in the epidermis. Although Q-switched lasers are widely considered to be the standard treatment for both epidermal and dermal pigmentary conditions, a very high risk of post-inflammatory hyperpigmentation (PIH) of up to 25% is seen in patients with skin of color. Recently, the novel picosecond laser with pulse durations operating at sub-nanosecond domains has been shown to be effective in tattoo removal and in the treatment of acne scars. The objective of this study is to examine the safety and efficacy of the dual wavelength picosecond laser for the treatment of benign pigmented skin lesions in Asian patients.

Methods: Twelve subjects with benign pigmentary disorders and Fitzpatrick skin types III to IV were recruited in a prospective clinical study to examine the safety and efficacy of the dual wavelength picosecond laser. Patients were treated at approximately 2-6 week intervals depending of the type of lesion. The primary efficacy endpoint is the global percent of clearance which was evaluated by blinded observers using post treatment photographs compared to baseline photographs. Safety was evaluated before and after each laser treatment and patients were asked to rate the level of pain according to the Visual Analog Scale after each treatment session. Patient satisfaction was assessed at the completion of treatment with questionnaires. All patients were followed up at 4, 8, and 12 weeks after the last treatment session.

Results: The pigmentary conditions treated included melasma, freckles, lentiginies, café au lait macules, and Hori's macules. Three months after treatment, 53.8% of all pigments achieved excellent response (75-94% lightening,) 30.8% of pigments achieved good response (50-74% lightening,) and 7.7% of pigments achieved both fair (25-49% lightening) and poor responses (0-24% lightening), respectively. The average number of treatment sessions required to reach at least 50% clearance was 4.5 for melasma, 1 for freckles, 1.5 for lentigines and 1 for café au lait. The patient with Hori's macules did not reach 50% clearance after a total of six treatments. Sixty three percent of patients reported satisfaction in the subjective assessment, while 27.3% were neutral and 9.1% were very dissatisfied. The post inflammatory hyperpigmentation rate was 4.8% and 6.5% of subjects developed blistering as a side effect of treatment.

Conclusion: The dual wavelength picosecond laser is a safe and effective treatment of benign pigmentary conditions in patients with skin of color. In particular, superior clinical efficacy is demonstrated for treatment of freckles and lentigines with a low risk of PIH. Lasers Surg. Med. 51:14-22, 2019. © 2018 Wiley Periodicals, Inc.

Keywords: Asians; picosecond; pigment; skin pigmentation.