Botulinum toxin type A in primary palmar hyperhidrosis - Randomized, single-blind, two-dose study

Background: Primary palmar hyperhidrosis is characterized by excessive swea ting due to increased sympathetic cholinergic sudomotor nerve traffic to th e palmar surface of the hands. Clinical studies suggest that intradermal in jections of botulinum toxin are effective in the treatment of palmar hyperh idrosis. Objectives: To establish the effectiveness of intradermal botulinu m toxin in reducing hyperhidrosis, to determine the most effective dose of toxin, and to examine its effect on muscle strength. Methods: In a prospect ive, single blind, randomized trial, 24 patients with severe palmar hyperhi drosis received either a low (50 U) or a high dose (100 U) of botulinum tox in type A (Botox, Allergan) injected intradermally in 20 sites in each palm . Results: Following injection with either dose, iodine starch test reveale d a significant decrease in sweating within the first month. Six months aft er injection, the anhidrotic effect was still evident in two thirds of the patients in both groups. Handgrip strength was not affected with either dos e but finger pinch strength, 2 weeks after the injection, decreased 23 +/- 27% with 50 U (p < 0.05) and 40 +/- 21% with 100 U (p < 0.001). Pinch stren gth improved gradually but 6 months after treatment it was still 7-11% lowe r than at baseline. Conclusions: Both 50 and 100 U of botulinum toxin type A, injected intradermally in each hand, decreased sweating in patients with primary hyperhidrosis for at least 2 months in all the patients, and 6 mon ths in most patients. Weakness in the intrinsic muscles of the hand was obs erved.