The relationship between clinical characteristics of melasma and sunscreen use in women: a cross-sectional, two-center study

Abstract

Melasma is associated with genetic factors, exposure to ultraviolet light, and hormonal influences. Because UV exposure is a crucial factor in the pathogenesis of melasma, the preventive effect of sunscreen use is established. This cross-sectional study investigated the relationship between the clinical features of melasma and the use of sunscreen among 126 women attending outpatient dermatology clinics in two centers. Patient's age, occupation, body mass index, use of photosensitizer drugs, hormone replacement therapy and, or oral contraceptive, and family history of melasma were thoroughly documented. Comprehensive information about the patients' sunscreen usage was also recorded. Melasma location and depth were evaluated, and the melasma severity index (MASI) score was calculated. The mean participant age was 39.67 years, mean disease duration 25.08 months, and mean MASI score 5.22. Fitzpatrick phototype III was the most common phototype. Melasma was widespread and dermal in most patients. Thirty-one percent of patients did not use sunscreen with SPF >50. The mean duration of sunscreen use was 23.85 months. MASI scores showed a significant difference based on sunscreen use status (P = 0.001). Year-round sunscreen use was associated with significantly lower MASI score (P = 0.001), whereas daily frequency and reapplication showed no relationship. Disease location was not associated with occupation and sunscreen use. In a multivariate analysis, melasma depth emerged as the strongest independent determinant of sunscreen use, whereas the year-round sunscreen use was independently associated with lower MASI scores.