Botulinum toxin A: its expanding role in dermatology and esthetics.

The use of botulinum toxin A in cosmetic dermatology has increased in popularity due to the efficacy and relative safety of the treatment. Botulinum toxin A is one of eight exotoxins produced by Clostridium botulinum, a Gram-positive, spore-forming anaerobe. Flaccid paralysis results from the denervation of muscle fibers at the neuromuscular junction after botulinum toxin A administration. While treating blepharospasm, the Carruthers incidentally found that botulinum toxin A improved glabellar frown lines. Dynamic rhytides occur in areas of dynamic motion. These types of lines may be improved with botulinum toxin A. There are two types of botulinum toxin A commercially available (BOTOX and Dysport); only BOTOX is currently available in the US. The efficacy and tolerability of BOTOX was best demonstrated with a multicenter, double-blind, randomized, placebo-controlled study of the efficacy and safety of botulinum toxin type A in the treatment of glabellar lines in 264 patients. There was a significantly greater reduction in glabellar line severity with BOTOX. The effect was maintained for the duration of the study (120 days). There was low occurrence (5.4%) of mostly mild blepharoptosis in the BOTOX group. In another prospective study, it was found that about 1% of BOTOX patients reported severe headache. Botulinum toxin A can provide an alternative treatment of palmar and axillary hyperhidrosis when options such as topical agents (aluminum chloride) and iontophoresis have failed.