External Application of Herbal Medicines for Acne Vulgaris: A Systematic Review and Meta Analysis

Aim of the study: The objective of this systematic review is to critically evaluate the evidence of the effectiveness and safety of external application of herbal medicines (EAHM) for acne vurgalis (AV). Methods: English, Chinese and Korean language databases were searched up to May 2018. Randomized clinical trials (RCTs) that reported the effects of EAHM for AV were included and analysed. Results: A total of 10 randomized trials with 656 AV patients were identified. A meta-analysis of two RCTs indicated that EAHM had a significant effect on improving primary outcome 'global assessment' compared with placebo (mean difference (MD) = -2.62, confidence interval (CI) = -4.84 to -0.40, p = 0.02). Furthermore, data extracted from two RCTs showed that EAHM significantly reduce primary outcome 'inflammatory lesion count of acne' (MD = -1.25, CI = -1.68 to -0.83, p < 0.00001) and 'non-inflammatory lesion count of acne' (MD = -1.32, CI = -1.75 to -0.90, p < 0.00001). No significant difference was observed between groups in secondary outcome 'sebum of skin' (MD = -0.21, CI = -0.53 to 0.11, p = 0.20) and 'patient-reported changes in symptom' (relative risk (RR) = 2.56, CI = 0.43 to 15.22, p = 0.30). No severe adverse events (AEs) were found and no treatment was stopped due to AEs of EAHM. Conclusions: EAHM seems to have affirmative effects, but quality of evidence, and non-standardized use of EAHM make our conclusion weak. Our suggestion is rigorously designed RCTs and standardization of EAHM are required in the future.