BACKGROUND: Post-inflammatory hyperpigmentation (PIH) is a major concern in laser treatment of dermal melanocytosis in pigmented skin, particularly when immediate whitening is used as the therapeutic endpoint. OBJECTIVE: To compare a computational model-guided non-whitening endpoint with the conventional whitening endpoint for treating acquired bilateral nevus of Ota-like macules (ABNOM) using a 755-nm picosecond alexandrite laser. METHODS: In this prospective, randomized, evaluator-blinded, split-face trial, 30 Asian patients (Fitzpatrick skin types III-V) underwent three sessions at 6-month intervals. One facial side received a larger spot size and lower fluence designed by a melanosome-disruption threshold fluence model to achieve a non-whitening endpoint. The contralateral side received a smaller spot size and higher fluence to achieve immediate whitening. RESULTS: Both endpoints achieved comparable and high clearance after three sessions (Global Aesthetic Improvement Scale >3.85/4). However, the whitening endpoint resulted in higher rates of PIH (22.6% vs 4.8%, P<0.05) and scabbing (61.9% vs 9.5%, P<0.05). Patient satisfaction was high for both approaches, with 68% preferring the non-whitening endpoint. LIMITATIONS: Single-center study with limited inclusion of Fitzpatrick skin types III-V. CONCLUSION: The model-guided non-whitening endpoint achieved comparable efficacy with less PIH and scabbing, supporting a safer strategy for ABNOM in pigmented skin.
Wang et al. (Fri,) studied this question.