Botulinum toxin A in the treatment of patients with Frey syndrome

Background: This was a prospective study of the treatment of Frey syndrome, also known as gustatory sweating, with botulinum toxin A. Methods: Thirteen patients with a mean involved skin area of 53 (range 36-80) cm(2), as assessed with the Minor starch-iodine test, were treated with 0.1 ml toxin (75 units/ml) injected intracutaneously into every 4 cm 2 of involved skin. The mean total dose was 100 (range 67.5-150) units. Treatment results were assessed every 3 months with the Minor test. The Frey Questionnaire Card (FQC) was used for subjective assessment. The mean follow-up after primary treatment was 20 (range 9-24) months. Treatment was repeated if the symptoms recurred. Results: After 3 months 11 of the 13 patients showed a decrease of gustatory sweating of more than 90 per cent. All but one patient with a follow-up of 2 years suffered recurrent gustatory sweating. The mean recurrence-free period after primary treatment was 11 months and that after secondary treatment was 15 months. FQC score and objective assessment correlated well. Treatments were well tolerated, although two patients developed a temporary perioral muscle paresis. Conclusion: Botulinum toxin A produces good results in the treatment of Frey syndrome. Repeated treatment improves on the results of primary treatment.