Essential oils as topical anti-infective agents: A systematic review and meta-analysis

Objective: This study summarized evidence on the efficacy and safety of essential oils (EOs) in the treatment of topical infections. Design and setting: Systematic review of clinical trials conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guideline. Electronic databases of the Cochrane, PubMed, EMBASE, Web of Science, and Scopus were searched from inception to November 2018. Intervention: Essential oil of any type, standard treatment and placebo. Main outcome measures: Outcomes of the study include total acne count, acne severity index, reduction in total acne surface area, number of non-inflammatory acne lesions and inflammatory acne lesions, microbial cure rate, microbial decolonization rate, and new microbial emergence. Results: Non-significant but higher proportion of MRSA was cleared in EOs group (69% [95%CI: 34%, 96%]) compared to routine care (45% [95%CI: 36%, 53%]). Essential oils significantly lowered level of new MRSA emergence (9% [95% CI: 5%, 14%], I-2 = 86.59%) compared to routine care (53% [95%CI: 30%, 75%], I-2 = 86.59%). Four of the five studies on acne treatment showed equal or superior efficacy of EOs and the remaining one showed inferior efficacy to a control. In treatment of topical fungal infections, efficacy of essential oils were non-inferior compared to a standard treatment but superior to a placebo. Conclusion: Essential oils could be considered as alternative treatment for acne, decolonization of MRSA, and topical fungal infections, yet the low quality and heterogeneity among the studies calls for further studies.