Hypopigmentation Following Picosecond Laser Treatment for Melasma: A Case Series

While hypopigmentation is rare with PSL treatment, it can occur even with conservative low-fluence settings and adequate intervals between sessions. One possible mechanism is thermal beam- stacking, where slow hand movement during treatment may lead to repeated pulses on the same area. This can result in localised thermal accumulation, potentially causing subcellular disruption of melanosomes without overt melanocyte loss. These findings suggest the need for clinician vigilance in monitoring for hypopigmentation, as re-pigmentation may not be achievable. Larger, controlled studies are needed to clarify risk factors and guide safer practice.