Botulinum toxin A for quality of life improvement in post-parotidectomy gustatory sweating (Frey's syndrome)

Objective: To measure patient-reported quality of life before and after botulinum toxin A treatment of post-parotidectomy Frey's syndrome (gustatory sweating). Patients and methods: A questionnaire concerning functional, social and emotional aspects of Frey's syndrome (14 questions, with responses on a zero to three point scale) was administered to 17 patients (13 women and four men) before and one month after intradermal injection of botulinum toxin A. Parotidectomy had been performed one to 19 years previously, for benign (n = 10) or malignant (n = 7) tumours, with gustatory sweating occurring a median of 15 months after surgery (range: one month to 14 years). Pre- and post-treatment quality of life scores were compared using Wilcoxon's test (p < 0.05). Results: Patients' reported functional quality of life improved significantly (p = 0.0004). Their social and emotional scores were not significantly modified (p = 0.155 and 0.142, respectively). Seven patients (41 per cent) found the injections painful, but all patients said that the effects were beneficial, that they would undergo new injections if necessary and that they would recommend this treatment to other patients. The benefit lasted over 1.5 years for 60 per cent of patients. No correlation was found between duration of the effect and the extent of parotidectomy (p = 0.067). Conclusions: Botulinum toxin A significantly improved patients' functional quality of life, without significant improvement in their social or emotional quality of life, according to our questionnaire results. The duration of the effect was longer than the reported physiological effect of botulinum toxin A on acetylcholine receptors.