Botulinum toxin treatment of secretory disorders.

Botulinum neurotoxin serotype A (BoNT/A) has revolutionised the treatment of a variety of autonomic hypersecretory disorders. Several open and controlled studies indicate that BoNT/A is a safe and effective treatment for focal hyperhidrosis of the axillae and palms, for gustatory sweating, and for some other rare conditions associated with focal hyperhidrosis. There is class I evidence for the efficacy of botulinum toxin in axillary hyperhidrosis and class II evidence for palmar hyperhidrosis and gustatory sweating. BoNT/A has the potential to replace current invasive and surgical techniques and should at least be considered as a viable alternative. The results of pilot studies to treat sialorrhea are encouraging. However, the optimal dose, best mode of application, side effects, and duration of BoNT/A action in this condition remain uncertain. We need further formal clinical trials to evaluate risks and benefits of BoNT/A for palliative treatment in of sialorrhea in Parkinson's disease and in bulbar amyotrophic lateral sclerosis. Based on the few reports published, BoNT/A injections into the lacrimal gland for hyperlacrimation may be an elegant method to treat this sometimes disabling condition. Again, larger studies are needed to evaluate the risks and long-term benefits of this treatment option.