Efficacy and safety of picosecond 755‐nm alexandrite laser for treatment of nevus of Ota in Taiwanese children: A retrospective study

Abstract

Objectives To evaluate the efficacy and safety of picosecond 755‐nm alexandrite laser in the treatment of nevus of Ota in children. Materials and Methods A retrospective study was conducted by reviewing medical charts and photographs of 86 Taiwanese children with various types of nevus of Ota between January 2017 and September 2020. Picosecond 755‐nm alexandrite laser therapy was used to treat pigmentary lesions. Percent clearance of lesions during treatment and the treatment time required to achieve 95%–100% clearance were determined. Results According to Tanino's classification or Peking University Medical College Hospital (PUMCH) classification of nevus of Ota, most patients belonged to Tanino's Type II (32%) and Type III (38%) or PUMCH Type IIb (33%) and Type IIIb (26%), which indicated that the nevus was mainly distributed in the forehead, upper and lower eyelid, zygomatic, cheek, and temple regions. After treatment with picosecond 755‐nm alexandrite laser, 96.5% of the patients achieved 95%–100% clearance with an average of 4.3 treatment sessions. The earlier onset of lesions (before 5 months of age) and the darker Fitzpatrick skin types (type IV vs. type III) significantly increased the number of treatments required to achieve clear response, while sex, age at first treatment, Tanino's classification of nevus, and color of nevus had no significant effect. Posttreatment hypopigmentation or hyperpigmentation was transient and resolved within 6 months. No serious response of the skin was evident. Conclusion Picosecond 755‐nm alexandrite laser treatment of nevus of Ota in children was safe and effective. The treatment was well‐tolerated, and only a few transient, minor side effects occurred.

Advancements in Laser Therapies for Dermal Hyperpigmentation in Skin of Color: A Comprehensive Literature Review and Experience of Sequential Laser Treatments in a Cohort of 122 Indian Patients

“…A recent study comparing the ps and ns forms of 755nm laser demonstrated superior efficacy and fewer side effects in the former [24]. Younger patients show better responses, requiring fewer sessions and less fluence [25,26]. Potential explanations include nevi darkening, darkening of the surrounding skin, and an increase in dermal melanocytes' histologic depth with advancing age [23].…”

Update on lasers in pediatric dermatology: how primary care providers can help patients and families navigate appropriate treatment options and timelines

“…1064 nm Q-switched Nd : YAG has also been shown to be well tolerated and effective in skin types V and VI, although there is risk of guttate hypopigmentation [23]. 755 nm picosecond Alexandrite and 1064 nm picosecond Nd : YAG have both been shown to be well tolerated and effective in treatment of Nevus of Ota [24,25]. 755 nm picosecond Alexandrite has demonstrated superiority to 755 nm Q-switched Alexandrite in terms of treatments needed, as well as posttreatment erythema and duration of postinflammatory hyperpigmentation after treatment [24][25][26][27].…”

“…755 nm picosecond Alexandrite and 1064 nm picosecond Nd : YAG have both been shown to be well tolerated and effective in treatment of Nevus of Ota [24,25]. 755 nm picosecond Alexandrite has demonstrated superiority to 755 nm Q-switched Alexandrite in terms of treatments needed, as well as posttreatment erythema and duration of postinflammatory hyperpigmentation after treatment [24][25][26][27]. Rates of recurrence after treatment are variable and depend on the number of treatments and clearance achieved, but clearance of 85% or higher is associated with a lower risk of recurrence [28 & ].…”

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

“…16 Comparative studies on nevus of Ota have shown that picosecond lasers, even at a lower fluence, have a lower incidence of complications with higher efficacy than nanosecond lasers. 17 By contrast, while some clinical studies reported significant differences in the efficacy between picosecond and nanosecond lasers for epidermal lesions, 18 others did not reach statistical significance. 19 To further distinguish the differences between picosecond and nanosecond lasers, it is essential to determine the optimal clinical endpoints for picosecond lasers.…”

“…Consequently, picosecond lasers can selectively disrupt melanosomes through rapid thermal expansion caused by a rapid temperature rise while minimizing thermal diffusion to adjacent tissue components 16 . Comparative studies on nevus of Ota have shown that picosecond lasers, even at a lower fluence, have a lower incidence of complications with higher efficacy than nanosecond lasers 17 . By contrast, while some clinical studies reported significant differences in the efficacy between picosecond and nanosecond lasers for epidermal lesions, 18 others did not reach statistical significance 19 .…”