Effect of botulinum toxin type A for treating hypertrophic scars: A split‐scar, double‐blind randomized controlled trial

Abstract Background Hypertrophic scars (HS) are a challenging disorder that mostly develops during wound‐healing process following skin injuries. Methods A split‐scar, double‐blind randomized controlled trial was held to assess the safety and efficacy of botulinum toxin type A (BTA) injection in hypertrophic scars (HS). Thirty patients with old scars (range: 1‐15 years) were treated, with sides randomized to receive treatment with either BTA or 0.9% normal saline once monthly for three consecutive months. Scars were assessed using the Vancouver scar scale (VSS) along with digital photograph standardization. Results Twenty‐one subjects completed the study. The mean VSS score for the BTA‐treated half of the scars decreased from 7.29 ± 2.327 before injection to 5.33 ± 2.41 following injection which was highly significant ( P = .01). For the control half, the mean VSS decreased insignificantly from 7.29 ± 2.327 before injection to 7.10 ± 2.234 following injection ( P = .104). Conclusion Clinical and cosmetic improvement was demonstrated significantly among the BTA‐treated group. BTA can be an additional and useful tool for improving scar outcomes.