Melasma is Associated with Lower Serum Vitamin D Concentrations as Compared to Healthy Controls

Background Melasma is a common, chronic skin condition of hyperpigmentation involving the appearance of symmetric and irregular light brown macules and patches, mainly on sun exposed skin of the head and neck. Though the pathogenesis is not fully understood, hyperfunctional melanocytes are known to deposit excess melanin in the epidermis and dermis. Known risk factors or triggers include genetic influence, hormonal influence, and ultraviolet radiation. Due to the avoidance of ultraviolet light, vitamin D supplementation is recommended. Due to known influence of vitamin D on the skin and the large prevalence of melasma in the public, the association between vitamin D and melasma will be examined further. Methods A retrospective review was performed utilizing the TriNetX platform to query de-identified patient data from the Medical University of South Carolina’s Electronic Health Record system over a 9-year period from January 2013 to May 2022. Calcidiol (25-hydroxy-vitaminD) was utilized as a surrogate for Vitamin D level. Statistical analyses were performed using Chi-square tests. Results Of 1,962 patients diagnosed with melasma, 840 had a serum calcidiol level measured following diagnosis. The majority of these patients were female (77%) and had an average age of 60.3 + 19.2 years. Melasma patients were most commonly Caucasian (81%), followed by African American (15%) and Hispanic or Latino (3%). Patients with melasma had an average serum calcidiol of 33.8 + 15.8 ng/mL (reference range: 25 – 80 ng/mL). This was significantly lower than comparison to 2,146 dermatology patients not diagnosed with melasma (36.8 + 15.8 ng/mL, p-value <0.0001%).   Conclusion Vitamin D has been demonstrated to be critical in the skin, including differentiation and proliferation of melanocytes. Our results suggest that patients with melasma, who have significantly lower levels of serum vitamin D than their healthy counterparts, may benefit from vitamin D supplementation. Future studies investigating improvement in melasma symptoms following vitamin D supplementation are needed.