Adjuvant botulinum toxin A in dyshidrotic hand eczema: a controlled prospective pilot study with left-right comparison.

OBJECTIVE: Dyshidrotic hand eczema is a therapeutic challenge. A prospective pilot study was performed with left-right comparison in order to investigate whether chemical de-innervation of sudoriferic nerves would be superior to standard therapy with topical corticosteroids.

BACKGROUND: Botulinum toxin A (BTXA) is a potent inhibitor of acetylcholine release, that induces eccrine sweat production and release. Inhibition of sweating by other measures such as tap water iontophoresis has been shown to be beneficial in dyshidrotic hand eczema.

METHODS: Eight adult patients suffering from dyshidrotic hand eczema (atopic type) were included in a prospective, side-by-side controlled clinical pilot study using topical corticosteroids on both hands in combination with intracutaneous injections of 100 units of BTXA (Botox) on the more severely affected hand on day 1. The dyshidrotic hand eczema was classified using the DASI (Dyshidrotic Eczema Area and Severity Index) before treatment (0), after 1 week, 4 weeks and 8 weeks.

RESULTS: Six patients completed the study, two dropped out because of social and personal reasons. The mean DASI score changed from 28 to17 with topical therapy alone and from 36 to 3 with adjuvant BTXA (P < 0.01). Itching and vesiculation were inhibited earlier when using the combination of corticosteroids and BTXA. There was one relapse in the corticosteroid group. Relapses have not been seen in the BTXA group.

CONCLUSIONS: Interruption of sweating by BTXA improves the outcome and reduces relapses in patients with dyshidrotic hand eczema. BTXA is antipruritic as well suggesting that it does not only interact with acetylcholine release but substance P.