Association Between Acquired Bilateral Nevus of Ota‐Like Macules Patients' Clinical Characteristics and Melasma Induction/Exacerbation After Q‐Switched Laser: A Decadal Comparative Study of 2675 Chinese Women in Two Different Periods

• DOI: 10.1002/lsm.70024
• Publication Date: 2025-05-23T05:04:24Z
• Authors: Ying Li; Ziyang Huang; Yiran Peng; Yingxue Huang; Wei Shi; Ben Wang; Yaling Wang; Dan Jian

ABSTRACTBackgroundPost‐laser melasma induction/exacerbation remains a critical challenge in treating acquired bilateral nevus of Ota‐like macules (ABNOMs). While laser parameters are well‐studied, patient‐specific risk factors across evolving therapeutic eras require elucidation.MethodsThis retrospective cohort analyzed 2675 ABNOMs patients treated with Q‐switched lasers in two eras: C1 (2010–2013; 1064 nm‐only, n = 1069) and C2 (2020–2023; multi‐wavelength, n = 1606). Risk factors were assessed through multivariate logistic regression, incorporating laser wavelength stratification.ResultsEra‐specific risk reversals emerged: In C1, age > 25, Fitzpatrick IV and patch lesions predicted melasma induction, whereas large/dark lesions showed protective effects. C2 showed inverse risks for lesion characteristics (large/dark lesions showed negative effects), with skin type/age becoming nonsignificant. Despite increased number of patients with pre‐existing melasma in C2, melasma exacerbation rates decreased from 87.6% (C1) to 50.1% (C2, p < 0.05) in parallel with diagnostic advances (subclinical melasma detection) and protocol optimization. Wavelength‐specific analysis revealed a persistent Fitzpatrick IV risk with 1064 nm versus lesion‐driven risks with 694/755 nm. Paradoxically, treatment of dark lesions with 1064 nm reduced the risk of melasma exacerbation, probably through selective melanin targeting.ConclusionABNOMs‐related melasma risks dynamically evolve with diagnostic/therapeutic advancements, demanding phenotype‐specific laser parameter selection. This decade‐spanning analysis provides actionable insights for optimizing laser therapy in diverse ABNOMs populations, despite inherent retrospective limitations.Clinical Trial RegistrationRegistry and the Registration No. of the study/trial: ChiCTR2500095697.