Beyond pigmentation: toward a melasma vascular assessment index for precision assessment of melasma

Melasma has traditionally been regarded as a pigmentary disorder and assessed predominantly using pigmentation-based instruments, particularly the Melasma Area and Severity Index (MASI) and modified MASI (mMASI). However, advances in molecular biology, histopathology, dermoscopy, and non-invasive imaging have expanded its biological model to include vascular remodeling, inflammation, dermal alterations, photoaging, and skin barrier dysfunction. Vascular involvement is increasingly recognized as biologically relevant, clinically observable, and potentially therapeutically actionable, yet its assessment remains heterogeneous and lacks a standardized clinical framework. In this Perspective, we propose the Melasma Vascular Assessment Index (MVAI) as a complementary framework for characterizing the vascular phenotype of melasma. We provide a provisional definition and identify three candidate domains: vascular extent/distribution, intensity/prominence, and morphology/pattern. These domains require empirical refinement before MVAI can be operationalized as a scoring instrument. We further propose a seven-stage roadmap encompassing construct refinement, content validation, scoring development, measurement-property evaluation, responsiveness, incremental clinical utility, and external validation. Integration with dermoscopy, quantitative imaging, and artificial intelligence-assisted analysis may subsequently enhance assessment. If validated, MVAI could complement MASI or mMASI by enabling parallel characterization of pigmentary and vascular manifestations, distinguishing residual disease components, evaluating vascular-targeted interventions, and informing mechanism-based treatment selection. This approach may advance precision assessment alongside precision treatment in melasma.