Treatment of gustatory sweating with botulinum toxin: A prospective study on long-term efficiacy and quality of life

Introduction: Gustatory sweating is a common complication of parotid gland surgery. Botulinum toxin A (BTX) is considered being effective. This study was designed to evaluate the efficacy on long-term and to value quality of life. Method: Seventeen patients with severe gustatory sweating were treated with injections of one unit/cm2 BTX intracutaneously. The evaluation relied on self-assesment of patients and on clinical examinations four weeks, four, eight, twelve and eigtheen month after treatment. Minor's test was performed and digital photograph aided to calculate affected skin area. Quality of life was evaluated by SF-36 before, six and eighteen month after treatment. Results: The efficiacy of BTX was exellent in the facial skin and less effective in hairy temporal region. Overall there was a median reduction of affected skin area from 30 cm2 to less than 2 cm2. Within eighteen month seven patients (41%) had a symptomatic recurrent gustatory sweating, five patients had an increase in Minor's test without clinical relevance and five patients had no signs of recurrent sweating at all. The overall data have shown an increase in affected skin over eigtheen month, but no significant changes (p=0.117). Quality of life increased over the time. Significant levels could be seen in 'Mental Health' and 'Social Function'. Conclusion: BTX has proven to be a save and highly effective in treatment of gustatory sweating which improves quality of life. 60% of the patients had an asymtomatic period of at least eighteen month. Keywords: botulinum toxin, gustatory sweating, Frey's syndrome