Oxidative stress in alopecia areata: a systematic review and meta-analysis.

Several studies have investigated the oxidative stress parameters in alopecia areata (AA) patients with variable results. This study aims to analyze the association between oxidative stress and AA based on current literature.A systematic review of the existing literature was performed in PubMed, Scopus, and Cochrane databases by two authors independently. Mean and standard deviation values of oxidative stress parameters of AA patients and healthy controls were extracted for quantitative analysis.A total of 18 studies were included in the analysis. Patients with AA had impaired oxidative balance with elevated levels of serum malondialdehyde, nitric oxide, and total oxidant capacity and lower levels of serum superoxide dismutase, paraoxonase, glutathione peroxidase, and total antioxidant capacity. Levels of oxidative parameters were significantly higher in severe AA compared to mild/moderate AA. Heterogeneity in the baseline characteristics of the included studies and limited available data for most parameters were the limitations of this study.Current evidence suggests that AA is associated with oxidative stress. More studies are needed to strengthen this association. Moreover, studies evaluating the role of antioxidant use in AA may be rewarding.