Frey's syndrome after parotidectomy: a retrospective and prospective analysis.

Gustatory sweating is a well-known sequela after parotid surgery. In a retrospective and prospective study of patients undergoing parotid surgery, the onset, time course, extent, and treatment modalities of Frey's syndrome were analyzed. Twenty-two percent of the patients evaluated by questionnaires and 43% of the patients followed prospectively within 1 year were found to be symptomatic. Although the Minor starch-iodine test was positive in 38% of patients at 3 months, none of these patients experienced symptoms. Up to 12 months after surgery the rate of patients who tested positive increased to 96% and the total area of sweating expanded to a mean value of 18 cm2. Whereas most of the patients are not markedly disturbed, few patients (5% to 10%) suffer from severe gustatory sweating. These patients present a therapeutic challenge.