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

J Cosmet Dermatol. 2020 Sep;19(9):2252-2258. doi: 10.1111/jocd.13627. Epub 2020 Jul 29.


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.

Keywords: botulinum toxin type A (BTA); fibrosis; hypertrophic scars (HS); wound healing.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Botulinum Toxins, Type A* / therapeutic use
  • Cicatrix, Hypertrophic* / drug therapy
  • Double-Blind Method
  • Humans
  • Treatment Outcome
  • Wound Healing


  • Botulinum Toxins, Type A