Nourishing yin method using herbal medicine for skin disease: A systematic review and meta-analysis

IntroductionNourishing yin is one of the most important treatment methods for skin diseases. The main conditions for which herbal prescriptions are used for nourishing yin are: skin pruritus, psoriasis, eczema, atopy, acne and alopecia. The aim of this systematic review was to identify and analyse trial data on the efficacy and safety of the nourishing yin method using herbal medicine for skin disease.MethodsEleven electronic databases were searched from their inception through until December 2016, with no language limitation. Randomised controlled trials for nourishing yin using herbal prescriptions used to treat skin disease were identified and their risk of bias of assessed.ResultsOf 725 of the total trials identified, 29 studies were included. Most studies had a high risk of bias. Twenty-five RCTs tested nourishing yin herbal medicines for various skin diseases compared with conventional medicines. Most showed superior response rates compared with conventional medicine, and 7 trials reported equivalent effects. The meta-analysis showed favourable effects of the nourishing yin method using herbal medicine for various skin diseases (n = 2813, RR: 1.20, 95% CI: 1.13 to 1.26, P < 0.00001, I2 = 62%). Four studies assessed the nourishing yin herbal medicine plus conventional medicine for various skin diseases compared to conventional medicine alone. All of these 4 trials showed positive effects and the meta-analysis also showed favourable effects (n = 497, RR: 1.14, 95% CI: 1.05 to 1.23, P = 0.0009, I2 = 37%).ConclusionThis review provides superior or equivalent effects of the nourishing yin method using herbal prescriptions for treating skin diseases compared with conventional medicines.