Frey's syndrome involves changes to facial skin following an injury to the auriculo-temporal nerve. It may develop after parotid surgery.


Synonym: auriculotemporal nerve syndrome


The auriculo-temporal nerve is the posterior branch of the mandibular nerve (division of the trigeminal nerve). Preganglionic fibers from the glossopharyngeal nerve reach the otic ganglion, which communicates with the mandibular nerve. The parotid branch carries secretomotor fibers to the parotid gland.



(1) sweating and flushing of facial skin following a gustatory stimulus (salivation)

(2) history of injury to the auriculo-temporal nerve, such as parotidectomy

(3) sweating is documented based on a positive Minor starch-iodine test (see below).



• The onset may take several months after parotid surgery with most patients affected within 1 year.


Minor starch-iodine test:

(1) Both parotid areas are painted with an iodine solution.

(2) The areas are then sprayed with starch powder.

(3) Salivation is stimulated by having the patient suck on a lemon-drop candy.

(4) A positive result is (a) The affected side changes color from white to purple and (b) The unaffected side remains white.


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