Risk factors for facial melasma in women: a case-control study.

BACKGROUND: Melasma is a localized chronic acquired hypermelanosis, common in adult women and which has an important impact on their life quality. Its pathology is unknown, despite some recognized triggering factors.

OBJECTIVE: To evaluate risk factors for developing facial melasma in women.

METHODS: This was a case-control study involving adult women with or without facial melasma, paired by age. Variables were grouped into hierarchical levels: personal characteristic data, exposure variables, links to hormonal stimuli and the State-Trait Anxiety Inventory questionnaire, Brazilian version. The data were analysed using conditional multiple logistic regression.

RESULTS: We evaluated 207 patients and 207 controls. The mean age was 38 years. Cases differed from controls for phototype, Amerindian ancestry [odds ratio (OR) 2·59], years of beach or rural residence (OR 1·06), time exposed to sun at work (OR 1·65), time exposed to sun in leisure activities (OR 1·04), antidepressant/anxiolytic use (OR 4·96), menstrual irregularity (OR 3·83), pregnancy history (OR 3·59), years of oral contraceptive use (OR 1·23) and anxiety scores (OR 1·08). A family history of melasma was reported in 61% of cases and 13% of controls (OR 10·40).

CONCLUSIONS: Facial melasma is independently associated with elements linked to pigmentation capacity, family ancestry, chronic sun exposure, sexual hormone stimuli, psychotropics and anxiety traits.