Effect and persistency of botulinum toxin iontophoresis in the treatment of palmar hyperhidrosis

The purpose of this study was to investigate the efficacy and persistence of the hypohidrosis induced by iontophoresis of botulinum toxin type A in patients with palmar hyperhidrosis. Eight patients with severe palmar hyperhidrosis participated in this study. Iontophoresis of botulinum toxin was applied to the patients' dominant (right) hand and the other hand was the control treated with normal saline. Gravimetry and iodine-starch tests were performed to evaluate the rate of sweating. The evaluation sessions were at baseline, 2 and 4 days, 1, 2, 3, 4, 8 and 12 weeks after treatment. The patients were also asked to fill out the Dermatology Life Quality Index questionnaire at 2, 4, 8 and 12 weeks after treatment. The mean sweating rate significantly reduced at the first, second, third and fourth week and the second and third month (P < 0.05) after the treatment in the right hand, and the third and fourth week (P < 0.05) after treatment in the left hand. Iontophoresis of botulinum toxin rapidly induced a quick reduction of sweating rate for at least 3 months with no pain, muscle weakness or other side-effects.