Botulinum Toxin Type A: Is It Really Useful in Improving the Aesthetic Results of Extrafacial Scars? A Prospective, Randomized, Double-Blinded Study

BACKGROUND The role of botulinum toxin type A (BoNTA) in scar prevention has been studied mainly in facial and cervical regions, but its effects on extrafacial scars remain unclear. This study evaluated BoNTA's impact on scar aesthetics and its potential modulation of the NLRP3 inflammasome in wounds on the back. METHODS A prospective, double-blind, randomized controlled trial was conducted with 23 participants undergoing fusiform excision of benign skin lesions. The treatment group received intradermal BoNTA injections immediately after suturing, while the control group received saline. Scar outcomes were assessed using the Patient and Observer Scar Assessment Scale (POSAS) and histologic analysis, including NLRP3 expression, at 6 months postsurgery. RESULTS No significant differences were found in the POSAS observer subscale scores between groups. However, the treatment group reported lower scar-related itching ( p = .018) in the POSAS patient subscale. NLRP3 expression increased in both groups over time ( p < .001), but no significant difference was observed between them. CONCLUSION Botulinum toxin type A did not significantly improve extrafacial scar aesthetics or reduce NLRP3 expression. However, it was associated with decreased scar-related pruritus. Further research is needed to elucidate BoNTA's potential anti-inflammatory effects on wound healing.