Double-blind trial of botulinum A toxin for the treatment of focal hyperhidrosis of the palms

We performed a randomized double‐blind study within‐group comparison in 11 patients to study the effect of subcutaneous injections of botulinum A toxin in focal hyperhidrosis of the palms. A total dose of 120 mU (mouse units) of botulinum A toxin (Dysport®) was injected into six different sites on one palm, whereas the other was injected with sterile saline. Objective quantification of sweat production was performed using digitized ninhydrin‐staincd sheets. Three weeks after treatment, the mean reduction of sweat production in the botulinum A toxin‐treated palms was 26% (P<0·001). after 8 weeks 26% (P= 0·002) and after 13 weeks 31% (P<0·001).Subjective assessment of sweat production by the patients using a visual analogue scale showed a 38% improvement in the botulinum A toxin‐treated palms at 3 weeks (P=0·002). 40% at 8 weeks (P=0·002) and 38% at 13 weeks (P= 0·002). Neither the objective measurement nor the subjective rating showed a statistically significant reduction of sweating in the placebo‐treated palms. Three patients reported reversible minor weakness of powerful handgrip after injection at the toxin‐treated site, lasting between 2 and 5 weeks.