The Therapeutic Efficacy of Botulinum Toxin in Treating Scleroderma‐Associated Raynaud's Phenomenon: A Randomized, Double‐Blind, Placebo‐Controlled Clinical Trial

Objective To assess the therapeutic efficacy of local injections of botulinum toxin type A (Btx‐A) in improving blood flow to the hands of patients with Raynaud's phenomenon (RP) secondary to scleroderma. Methods In this randomized, double‐blind, placebo‐controlled clinical trial, patients with scleroderma‐associated RP received Btx‐A (50 units in 2.5 ml sterile saline) in one randomly selected hand and sterile saline (2.5 ml) in the opposite hand. Follow‐up at 1 and 4 months postinjection included laser Doppler imaging of hands, patient‐reported outcomes, and physical examination. We compared outcomes using paired t‐tests and population‐average generalized models with generalized estimating equations. Results Of 40 patients enrolled, 25 had limited scleroderma and 15 had diffuse scleroderma. From baseline to 1‐month follow‐up, there was a greater reduction in average blood flow in Btx‐A–treated hands compared to placebo‐treated hands. The model estimated that this difference was statistically significant (average difference −30.08 flux units [95% confidence interval −56.19, −3.98], P for interaction = 0.024). This difference was mainly influenced by patients with longstanding RP and diffuse scleroderma. Change in blood flow at 4‐month follow‐up was not significantly different between groups. Clinical measures (QuickDASH, McCabe Cold Sensitivity Score, pain on a visual analog scale, and Raynaud's Condition Score) improved slightly for Btx‐A–treated hands. Conclusion Our laboratory‐based laser Doppler imaging flow data do not support using Btx‐A to treat RP in all scleroderma patients. The secondary clinical outcomes suggest some positive effect, but its clinical meaningfulness is questionable. The role of Btx‐A in treating RP should be further studied with more homogeneous patient populations and in unique clinical situations such as acute digital ischemia.