Comparison of the Efficacy of 1064- and 730-nm Picosecond Lasers for Acquired Dermal Melanocytosis

Background: Acquired dermal melanocytosis (ADM) is a pigmentary lesion caused by melanocytes in the dermis. These conditions are refractory, and a consensus on treatment remains elusive. Aims: To compare the efficacy of 730- and 1064-nm picosecond lasers in the treatment of ADM and to supplement the comparison with a literature review. Patients:. We retrospectively examined patients who underwent picosecond laser therapy between April 2021 and February 2024. Treatments were performed three times with spot irradiation using a 730-nm laser (3-mm spot, 1.7–1.8 J/cm²; or 2-mm spot, 2.5–3.25 J/cm²) and a 1064-nm laser (3-mm spot, 3.1–4.0 J/cm²). Two months after each procedure, patient satisfaction was evaluated using questionnaires, macroscopic findings were assessed using photographs, and melanin accumulation was analyzed using skin analysis software. Evaluations were conducted on a 4-point scale (excellent, good, fair, and poor), with good or higher considered effective. Results: Seventy-eight and 83 patients were assigned to the 730- and 1064-nm groups, respectively. After three sessions, the 730-nm group exhibited superior outcomes in terms of subjective symptoms (patient satisfaction), objective findings, and software analysis improvements. The incidence of hyperpigmentation was 15.4% in the 1064-nm group and 14.5% in the 730-nm group, with no significant differences observed in the rates of other complications. Conclusions: The use of a 730-nm picosecond laser, which possesses high melanin selectivity, relatively deep penetration, and a short pulse width, suggests a potentially more effective treatment for ADM, compared to the effects of the conventional 1064-nm wavelength, without increasing complications.