Efficacy of botulinum toxin type A injection for Raynaud's phenomenon and digital ulcers in patients with systemic sclerosis.

Introduction: Systemic sclerosis (SSc) is an autoimmune, connective tissue disorder of unknown etiology which causes vasculopathy and fibrosis. Raynaud's phenomenon (RP) is a common complication of SSc, which leads to ischemia and gangrenes. Treatment of RP is a clinical problem and often remains insufficient.This study aimed to evaluate the therapeutic efficacy of local injections of botulinum toxin type A (BTX-A) in improving the symptoms of Raynaud's phenomenon (RP) secondary to scleroderma.

Material and methods: This parallel single-blinded, placebo-controlled clinical trial enrolled 29 patients with scleroderma. Participants received BTX-A in the first, 2^nd, 3^rd, and 4^th dorsal web spaces and the base of the thumb and small finger of the non-dominant hand and 2.5 ml of sterile normal saline in the opposite hand. Pre-injection measurements and post-injection follow-up evaluations at months 1 and 4 were performed. We compared the outcomes using the paired Student's t-test.

Results: The change in pain severity between pre-injection and month 1 follow-up was significantly larger in the BTX-A group (p-value = 0.04). Between pre-injection and month 1 and month 4, the changes in the Raynaud's condition score (RCS) (p-value = 0.02, 0.004, respectively) and the number of Raynaud's attacks (p-value = 0.006, 0.001, respectively) were significantly greater in the BTX-A group. No significant difference was found in terms of paresthesia, skin thickening, upper extremity function, ulcer diameter, number of ulcers, or Raynaud's attack duration between the two groups (p-value > 0.05). In time, the decrease in pain severity, paresthesia, RCS, number of ulcers, and ulcer diameter, and the increase in upper extremity function were significantly greater in the BTX-A group as compared to the placebo group (p < 0.05).

Conclusions: Our study showed that local injection of BTX-A is safe and has beneficial therapeutic effects on RP and RP-related digital ulcers in SSc patients.