The Efficacy of Onion Extract on the Prevention or Treatment of Scars: A Systematic Review

Scars are common and debilitating outcomes of burn injury, with no current consensus regarding the gold standard in scar management. Noninvasive interventions such as silicone gels are popular adjuvant treatments due to ease of application. Onion extract (OE) has been proposed as a potential scar treatment modality due to its antimicrobial and anti-inflammatory properties. A systematic search of the literature was conducted using PubMed, Scopus, and Cochrane for articles published between January 2000 and December 2021. Inclusion criteria were studies (1) involved OE gel or OE treatment and (2) those assessing scar prevention or treatment outcomes. Patient and physician reported scar outcomes after treatment and adverse effects were recorded. A total of 21 articles were included in the final review. Five studies found statistically significant improvements in overall scores and individual Vancouver Scar Scale components in the OE treatment group compared to the silicone groups. Several studies found that combined treatment of OE with other topical treatment modalities such as triamcinolone or silicone gel produced significant improvements in scar symptoms. In this review, reported adverse effects were minimal, often consisting of self-resolving pruritus, irritation, and erythema. This review supports OE's potential utility in scar prevention and treatment. Most studies reported minimal adverse events with OE application and significant benefits in specific scar characteristics. Further research is needed to investigate scar outcomes after treatment with OE with larger sample sizes and a follow-up period greater than a year.