730-nm Picosecond Laser Is More Effective Than 1064-nm for Acquired Dermal Melanocytosis

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A recent study compared 1064- and 730-nm picosecond lasers for Asian patients with acquired dermal melanocytosis.¹ It was determined that the 730-nm wavelength picosecond laser saw more cosmetic improvement with high tolerability and fewer sessions. The 730-nm laser has higher melanin selectivity, deeper penetration, and a shorter pulse width compared to its counterpart.

The retrospective analysis took place at 2 institutions between April 2021 and February 2024. There were 78 patients in the 730-nm group (3-mm spot, 1.7–1.8 J/cm²; or 2-mm spot, 2.5–3.25 J/cm²) and 83 patients in the 1064-nm group (3 mm spot, 3.1–4.0 J/cm²). All participants were Asian and female. The average age was 34.3 years. Over 95% of patients had a Fitzpatrick skin type between III and IV. Patients were clinically diagnosed with acquired dermal melanocytosis, but no biopsies were performed to confirm. Nearly 65% of the participants also had melasma.

The 1064-nm wavelength had a pulse width of 339 ps while the 730-nm wavelength had a pulse width of 246 ps. Each therapy was performed 3 times with targeted spot irradiation on each pigmented legion. For post-treatment care, participants were instructed to apply 3% prednisolone valerate acetate cream twice daily for 5 days. Sun protection was also highly recommended.

Evaluations were conducted at 2 weeks and 2 months after each procedure via 4-point scales. A score of “excellent” was equal to improvement between 76% and 100%. Patient satisfaction, macroscopic findings, and melanin accumulation were measured using questionnaires, photographs, and VISIA skin analysis software, respectively.

The 730-nm device had better outcomes compared to the 1064-nm laser. After 3 sessions, the 1064-nm group demonstrated 59% efficacy while the 730-nm group had an efficacy rate of 88%. Patient-reported satisfaction was higher among those who were treated with the 730-nm laser (93.9% versus 47.4%, respectively). The VISIA analysis also showed a higher level of improvement at 95.2% compared to 60.3%.

The incidence of hyperpigmentation was 15.4% in the 1064-nm group and 14.5% in the 730-nm group. Only 8.33% of these cases of hyperpigmentation in the 730-nm cohort occurred after a single session. Interestingly, 100% of patients who experienced hyperpigmentation in the 1064-nm cohort also had melasma (n = 12). In the opposite group, only 58.3% of those who had hyperpigmentation had melasma as well. No other significant complications such as hypopigmentation, scarring, and changes in texture were observed, and the treatment was well-tolerated in all patients. Potential study limitations include the lack of racial diversity in the patient population, the short follow-up period, and the limited number of treatment sessions.

Acquired dermal melanocytosis is more prevalent in women, especially those with darker skin tones.² Common laser therapies for acquired dermal melanocytosis include Q-switched ruby lasers, Q-switched alexandrite lasers, and scanning CO² lasers. This study is the first of its kind to evaluate a 730-nm picosecond laser for the treatment of acquired dermal melanocytosis, specifically in patients with non-white skin.

“Treating pigmentary disorders in patients with non-white skin types, including Asians, remains challenging due to the increased risk of laser treatment-related adverse effects, and consensus protocols are yet to be established,” the authors wrote. “The potential side effects and relative paucity of evidence regarding acquired dermal melanocytosis laser treatment in this population often result in prolonged treatment durations and frequent incomplete clearance.”

References

1. Takaya K, Kishi K. Comparison of the Efficacy of 1064- and 730-nm Picosecond Lasers for Acquired Dermal Melanocytosis. J Cosmet Dermatol. 2025;24(3):e70123. doi:10.1111/jocd.70123

2. Zhang Q, Jiang P, Tan C, Yang G. Clinical profile and triggering factors for acquired, bilateral nevus of Ota-like macules. Cutan Ocul Toxicol. 2017;36(4):327-330. doi:10.1080/15569527.2017.1287191