Melasma is manifested by symmetric hyperpigmentation of the sun-exposed skin; ultraviolet (UV) radiation is a known risk factor.

A new study published in Photodermatology, Photoimmunology & Photomedicine examined whether skin sensitivities to UVA and/or UVB differ between healthy controls and female patients with melasma.

In this study, the minimal erythema dose – from (MED)-UVA and MED-UVB, were compared between female patients with melasma and healthy controls. In addition, relationships between MED values, Melasma Area and Severity Index (MASI) scores and skin color were assessed.

Overall, the melasma and control groups included 142 and 137 Chinese women, respectively. The findings showed that the melasma group had lower MED-UVA and MED-UVB compared to the healthy control group. Meanwhile, MASI scores were negatively correlated with MED-UVA and MED-UVB. 

From the results, it was concluded that patients with melasma exhibit a low MED to both, UVA and UVB, which confers an increased UV sensitivity. Therefore, sun exposure should be avoided in these populations to alleviate or prevent melasma.

Source: Photodermatology, Photoimmunology & Photomedicine. 2021 Jun 25. doi: 10.1111/phpp.12713.