The place of botulinum toxin type A in the treatment of focal hyperhidrosis

Conflicts of interest: none declared. Sir, I read with great interest the paper by Lowe et al.1 in which they discuss the place of botulinum toxin type A (BTX‐A) in the treatment of focal hyperhidrosis (HH) and propose, based on published data, an algorithm for axillary HH and a second for palmar HH. I agree with the authors that topical medications should be used as first‐line therapy where practical. In that sense I would like to indicate that treatment with supersaturated concentrations of aluminium chloride (AlCl3) ranging from 25% to 50% in a 4–6% salicylic acid (SA) gel should be considered, particularly on the palms and soles,2 alone or in combination with other therapeutic modalities such as iontophoresis and BTX‐A, before resorting to surgery. Even patients with axillary HH, who failed to respond to AlCl3 in alcohol or did not tolerate it, found AlCl3 in the gel formulation3 more effective and better tolerated. The details of this extemporaneous formulation have already been published.4