Botulinum toxin type A for Frey's syndrome: a preliminary prospective study.

Fourteen patients with severe Frey's syndrome (occurring after conservative parotidectomy) managed with intracutaneous injection of botulinum toxin type A were prospectively evaluated. Results were analyzed for effectiveness, complications, and adverse effects. Complications were not encountered. The only adverse effect noted was a temporary and slight partial paresis of the upper lip of 3 months' duration in 2 patients. Permanent paresis was not encountered. Frey's syndrome was always controlled within 2 days following the intracutaneous injection of botulinum toxin A. Frey's syndrome recurrence was not encountered with a follow-up duration that varied from 3 to 9 months (mean follow-up 7 months). This preliminary report confirmed that in patients who have Frey's syndrome after conservative parotidectomy, the intracutaneous injection of botulinum toxin is a valuable treatment option that should be further investigated.