Association of Melasma with Thyroid Disorders

Abstract

Melasma, a common hyperpigmentation disorder, has been a subject of increasing interest due to its potential association with thyroid disorders. This systematic review and meta-analysis aimed to assess the relationship between melasma and thyroid function indicators, including thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), and thyroid antibodies, particularly anti-thyroid peroxidase (anti-TPO) and antithyroglobulin antibody. A comprehensive search across multiple databases identified 39 relevant studies for analysis. The systematic review and meta-analysis were ultimately conducted based on the data extracted from these 39 selected studies. The meta-analysis revealed significant differences in thyroid function indicators between individuals with melasma and control groups. Melasma patients exhibited higher TSH levels (SMD = 0.33, 95% CI: 0.18, 0.47) and lower T4 levels (SMD = -1.50, 95% CI: -2.96, -0.04). However, no significant difference in T3 levels was observed (SMD = -0.01, 95% CI: -0.20, 0.19). Notably, the presence of anti-TPO antibodies was significantly associated with melasma (Fisher = 26.80, P = 0.020). Gender-specific analyses revealed more pronounced thyroid function differences among women with melasma, suggesting potential hormonal influences. Melasma predominantly affects women and often exhibits exacerbations during pregnancy, indicating a complex interplay between sex hormones and thyroid function in pigmentation regulation. These findings have clinical implications for dermatologists and endocrinologists. Dermatologists should consider thyroid evaluation in melasma patients, especially in cases with treatment resistance. For endocrinologists, melasma could serve as a cutaneous marker for underlying thyroid dysfunction, particularly in women. Further research is needed to elucidate the mechanisms underlying this association and its temporal aspects. Longitudinal studies could provide insights into whether thyroid ........