Recurrent gustatory sweating Frey Syndrome after intracutaneous injection of botulinum toxin type A - Incidence, management, and outcome

Objective: To evaluate the duration of effectiveness of intracutaneous inje ction of botulinum toxin type A. for gustatory sweating as well as the inci dence, severity, management, and outcome of recurrent gustatory sweating. Design: An inception cohort with a minimum of 18 months of follow-up. Setting: A tertiary care center and university teaching hospital. Patients: Thirty-three patients with severe gustatory sweating. Intervention: Intracutaneous injection of 25 to 175 IU (mean, 86 IU) of bot ulinum toxin type A. Main Outcome Measures: Analysis of the effectiveness of the intracutaneous injection of botulinum toxin type A using the Kaplan-Meier actuarial life-t able method; completion of the Minor starch-iodine test in patients without symptomatic recurrent gustatory sweating; and the patients' self-assessmen t of the severity of the recurrent gustatory sweating. Results: The 1-, 2-, and 3-year actuarial estimate for symptomatic recurren t gustatory sweating was 27%, 63%, and 92%, respectively. In the 7 patients without symptomatic recurrent gustatory sweating, the Minor starch-iodine test revealed persistent gustatory sweating in 6, resulting in an overall 9 7% rate (32 of 33 patients) for recurrent gustatory sweating. No statistica l relationship could be demonstrated between the duration of effectiveness, the incidence of recurrent gustatory sweating, the severity of recurrent g ustatory sweating, and the following variables: age, sex, cause of gustator y sweating, skin surface involved, and dose of botulinum toxin type A injec tion. Within the group of 26 patients with symptomatic recurrent gustatory sweating, (1) the severity of the recurrent gustatory sweating was always r educed when compared with the severity of the initial gustatory sweating, a nd (2) the recurrent gustatory sweating always remained amenable to reinjec tion of botulinum toxin type A. Conclusions: The present series demonstrated a linear regression in the eff ectiveness of the intracutaneous injection of botulinum toxin type A in pat ients with gustatory sweating, while no factors appeared to be statisticall y related to the duration of effectiveness and/or the incidence of recurren t gustatory sweating. However, because the severity of recurrent gustatory sweating is reduced when compared with the severity of the initial gustator y sweating and because recurrent gustatory sweating remains amenable to rei njection of botulinum toxin type A, we believe that the intracutaneous inje ction of botulinum toxin type A should become the first-line treatment opti on in patients with gustatory sweating.