Is Botulinum Toxin Useful in Systemic Sclerosis Related Peripheral Vasculopathy? A Literature Review

Introduction: In systemic sclerosis (SSc), peripheral vasculopathy presents typically as Raynaud Phenomenon (RP) and Digital Ulceration (DU). Over the last decade, botulinum toxin (BT) has been reported effective in this scenario. Our goal was to review existing literature evaluating the efficacy of BT on RP/DU in SSc.

Materials and methods: We performed a search in Pubmed with the MeSH terms "systemic sclerosis" and "botulinum toxin". Original studies evaluating BT in the treatment of SSc-associated RP/DU were considered for inclusion. Results were screened by title, abstract and full-text.

Results: We identified 30 results, of which 5 original papers were included: 2 randomized controlled trials (RCT), 2 case series and 1 case control study, from a total of 133 patients. Only one RCT showed negative results, with worse blood flow in treated arm, but with lower dose of BT. Despite this, all 5 included studies reported improvement of at least 1 RP/hand function outcome measure. Concerning DU healing, resolution of baseline DU at the end of follow-up was reported in 75-100% of the patients, with 1 RCT showing superiority over placebo. The only reported adverse effect was transient hand weakness, affecting only 0-16.7% of patients. BT injection protocols were highly heterogeneous.

Conclusion: Despite conflicting results in 1 RCT, evidence points BT as an option in the treatment of SSc-related peripheral vasculopathy. However, future larger prospective trials are necessary to corroborate this hypothesis.