Preventive effect of levodopa on vitiligo development: a nationwide case–control study

Dear Editor, Levodopa, an amino acid precursor of dopamine and melanin, has been widely used to treat patients with Parkinson disease. Although the incidence of levodopa‐induced cutaneous adverse reactions has not been fully evaluated, recent studies have revealed that melanocyte‐associated skin adverse reaction is the most common.1 Cases of darkening of white hair following levodopa therapy for Parkinson disease have been reported.2 Notably, in vitro studies have revealed the protective effect of levodopa on neuronal cells.3 Therefore, we speculated that levodopa may exert a protective effect on melanocytes and could prevent vitiligo development. We conducted a nationwide, population‐based, case–control study to investigate the association between levodopa use and vitiligo development using the Korean National Health Insurance (NHI) claims database. We first identified all patients with vitiligo aged ≥ 40 years who met a physician at least four times between January 2007 and December 2017 with a diagnosis of vitiligo (vitiligo group). The control individuals had no history of vitiligo and were propensity score matched for age, sex and insurance type. We identified levodopa use in both groups before the first visit date when vitiligo was diagnosed (in the vitiligo group) and conducted conditional logistic regression analyses to explore the association of levodopa use and vitiligo development. All analyses were conducted using SAS software (version 9·4; SAS Institute, Cary, NC, USA). This study was approved by the institutional review board of St Vincent’s Hospital (VC17ZESI0090).