Botulinum Toxin in the Treatment of Focal Hyperhidrosis and Dyshidrotic Hand Dermatitis

Sammanfattning: Excessive sweating may cause considerable disability, with psychological, social and occupational consequences. Primary hyperhidrosis may also play a key role in the pathogenesis of dyshidrotic dermatitis and some other skin diseases.The aim of the present work was to evaluate a novel treatment of hyperhidrosis namely chemical sweat gland denervation with botulinum toxin type A (Btx A). The effects of multiple intradermal injections of Btx A (total dose Botox® 0.5 U/cm2 on one occasion) were evaluated in palmar and axillary hyperhidrosis, using patients as their own controls. The abolition of sweating was objectified by comparing measured evaporation and the size of the sweating area assessed in iodine-starch tests between the treated and untreated side before and one week after unilateral injections. Hyperhidrosis disappeared or was highly reduced in 22 of 26 patients with an effect duration of 8-9 months in most patients. Side-effects of palmar Btx A injections were restricted to a transient weakness of the hand muscles. This was studied by measurements of compound muscle action potentials of intrinsic muscles of the hand at supramaximal nerve stimulation and of muscle strength before and 3 weeks after treatment with Btx A and at a late follow-up after 15 – 37 weeks. Post-treatment values of these measures of intrinsic hand muscle function were significantly reduced at 3 weeks and had almost returned to normal at 37 weeks. Sweat gland histology and immunoreactivity were studied in skin biopsy specimens taken before and 2.5 – 6 months post-treatment. The lumen of the secretory tubule was diminished, but no atrophy of sweat gland cells was seen. A tendency to reduced staining with the neuronal marker PGP 9.5 suggested sudomotor nerve degeneration. Immunoreactivity of the neurotransmitters VIP and CGRP was unchanged.Patients with primary focal hyperhidrosis were found to have a marked reduction of life quality (increased Dermatology Life Quality Index score) – a reduction which, however, was almost reversed at measurement 5 months after treatment with Btx A.Ten patients with vesicular hand dermatitis were treated unilateraly with Btx A. Seven out of ten displayed marked improvement in both objective and subjective ranking measures of the dermatitis.In conclusion, focal hyperhidrosis and dyshidrotic hand dermatitis may be effectively treated with intradermal injections of botulinum toxin. Side-effects occur, but are minor and transient. The reduced sweat production is associated with minor changes in sweat gland histology and innervation. The considerably impaired quality of life demonstrated in patients with primary hyperhidrosis can be largely reversed by intradermal Btx A therapy.