UV-B irradiation attenuates dermal effects of botulinum toxin A: a randomized, double-blind, placebo-controlled study.

BACKGROUND Botulinum toxin type A (BoNT/A) is frequently used for cosmetic indications and hyperhidrosis. OBJECTIVES We investigated whether UV-B irradiation alleviates the BoNT/A effect on local sudomotor activity. MATERIALS AND METHODS In a randomized, double-blinded trial, the anhidrotic areas after BoNT/A (100 mU) injection 48 hours before and 14 days after UV-B irradiation were compared in six healthy volunteers. RESULTS UV-B irradiation alleviated BoNT/A effect by approximately 30% (p=.0017). The UV-B-evoked reduction of anhidrotic areas was constant over the observation period of 14 weeks. CONCLUSIONS When BoNT/A is applied intradermally, excessive exposure to UV-B and sunburn should be reconsidered. The authors have indicated no significant interest with commercial supporters.