Frey's syndrome is caused by:
Frey's syndrome is gustatory sweating i.e. when the patient eats, he has sweating over the cheek skin over the parotid. In section of auriculotemporal nerve during parotid surgery, the nerve aberrantly reconnects with the sympathetic sweat glands of the skin overlying the parotid.
Aberrant reinnervation of parasympathetic fibres of auriculotemporal nerve with sympathetic sweat glands
Aberrant reinnervation of parasympathetic fibres of auriculotemporal nerve with Greater superficial petrosal nerve
Abnormal cross innervation of Facial nerve with greater auricular nerve
Abnormal cross innervation of Facial nerve with auriculotemporal nerve
Facial Nerve and its disorders