Melasma represents the most obvious and disfiguring change of the face leading to psychological problems, especially in females. Ablative lasers have been used by many professionals to treat melasma, although scarce scientific dataexist, supporting this indication. The exact mechanism of action of ablative lasers in melasma is not yet clear enough.

The aim of a recent study published in Ultrastructural Pathology was to evaluate the ultrastructural effect of fractional ablative CO2 (FrCo2) laser on facial melasma.

In this study, eleven melasma patients evaluated clinically by clinical modified area and severity index (MASI) score, were treated by two sessions of fractional CO2 laser, one month a part. Two punch biopsies of 2 mm diameter were obtained from all subjects, one before and the other three months after treatment. All biopsies were analyzed by light and electron microscopy.

The results showed clinically, significant improvement of pigmentation and 48% reduction of (MASI) score after two sessions of laser treatments. Light microscopic analysis of specimens revealed significant decrease in melanocyte count after treatment. Electron microscopic analysis of specimens after treatment revealed significant decrease in the number and size of melanocytes and significant decrease or complete absence of melanin granules in the surrounding keratinocytes compared to pre-treatment specimens. While there was no scarring or post inflammatory hyper or hypopigmentation.

In inference, it was stated that repeated application of Fractional CO2 laser on melasma skin may result in long lasting improvement due to its destructive effect on melanocytes.

Source: Ultrastructural Pathology. 2019;43(4-5):135-144.doi:10.1080/01913123.2019.1673861.