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

Melasma is associated with genetic factors, UV-light exposure, and hormonal influences. Because UV exposure is a crucial factor in the pathogenesis of melasma, the preventive effect of sunscreen use has been established. This cross-sectional study investigated the relationship between the clinical features of melasma and sunscreen use among 126 women attending outpatient dermatology clinics at two centers. Patient's age, occupation, body mass index, use of photosensitizer drugs, hormone replacement therapy and/or oral contraceptive, and a family history of melasma were thoroughly documented. Comprehensive information on patients' sunscreen use 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, the mean disease duration was 25.08 months, and the mean MASI score was 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 a sun protection factor > 50. The mean duration of sunscreen use was 23.85 months. MASI scores showed a significant difference based on sunscreen use status (P = .001). Year-round sunscreen use was associated with significantly lower MASI scores (P = .001), whereas daily frequency and reapplication showed no relationship with MASI scores. Melasma location was not associated with occupation or sunscreen use. In multivariate analysis, melasma depth was the strongest independent determinant of sunscreen use, whereas year-round sunscreen use was independently associated with lower MASI scores.