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 injection of botulinum toxin type A. for gustatory sweating as well as the incidence, 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 botulinum 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-table method; completion of the Minor starch-iodine test in patients without symptomatic recurrent gustatory sweating; and the patients' self-assessment of the severity of the recurrent gustatory sweating. Results: The 1-, 2-, and 3-year actuarial estimate for symptomatic recurrent 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 97% rate (32 of 33 patients) for recurrent gustatory sweating. No statistical relationship could be demonstrated between the duration of effectiveness, the incidence of recurrent gustatory sweating, the severity of recurrent gustatory sweating, and the following variables: age, sex, cause of gustatory sweating, skin surface involved, and dose of botulinum toxin type A injection. Within the group of 26 patients with symptomatic recurrent gustatory sweating, (1) the severity of the recurrent gustatory sweating was always reduced when compared with the severity of the initial gustatory sweating, and (2) the recurrent gustatory sweating always remained amenable to reinjection of botulinum toxin type A. Conclusions: The present series demonstrated a linear regression in the effectiveness of the intracutaneous injection of botulinum toxin type A in patients with gustatory sweating, while no factors appeared to be statistically related to the duration of effectiveness and/or the incidence of recurrent gustatory sweating. However, because the severity of recurrent gustatory sweating is reduced when compared with the severity of the initial gustatory sweating and because recurrent gustatory sweating remains amenable to reinjection of botulinum toxin type A, we believe that the intracutaneous injection of botulinum toxin type A should become the first-line treatment option in patients with gustatory sweating.