Frey’s syndrome



Frey’s syndrome is a rare neurological disorder resulting from damage to or near the parotid glands responsible for making saliva, and from damage to the auriculotemporal nerve often from surgery.


It is characterized by gustatory sweating, flushing or both and as a result from damage to parasympathetic nerve fibers within the parotid gland, with subsequent reinnervation of sweat glands in the skin.


The condition is rare.


Its exact incidence is unknown.


Frey syndrome development after a parotidectomy  estimates range from 30-50 percent, and approximately 15 percent of affected individuals rate their symptoms as severe. 


Damage to the parasympathetic nerves typically occurs during surgery to the parotid gland, but facial trauma is another recognized cause.


It affects males and females in equal numbers.


The symptoms of the  syndrome are redness and sweating on the cheek area adjacent to the ear.


Findings can appear when the affected person eats, sees, dreams, thinks about or talks about certain kinds of food which produce increased salivation.


Sweating in the affected region after eating a lemon wedge suggests the diagnosis.


Sometimes burning pain occurs in  the same area.


Between attacks of pain there is sometimes numbness or other altered sensations.


The auriculotemporal branch of the mandibular (V3) branch of the trigeminal nerve carries parasympathetic fibers to the parotid salivary gland and sympathetic fibers to the sweat glands of the scalp. 


Severence and inappropriate regeneration of the auriculotemporal branch of the mandibular (V3) branch of the trigeminal nerve its parasympathetic nerve fibers may switch course to a sympathetic response, results in sweating in the anticipation of eating, instead of the normal salivatory response.


The syndrome is seen in patients who have undergone  thoracic sympathectomy, a surgical procedure wherein part of the sympathetic trunk is cut or clamped to treat sweating of the hands or blushing. 


Additionally, the findings can also include discharge from the nose when smelling certain food.


Rarely associated with 


accidental trauma, local infections, sympathetic dysfunction and pathologic lesions within the parotid gland.


Diagnosis is based on clinical signs and symptoms and a starch iodine test.


The Minor Iodine-Starch test consists of painting the affected area with iodine which is allowed to dry, then dry corn starch is applied to the face. 


In the presence of sweat the starch turns blue on exposure to iodine.


Treatments include: 


Topical anticholinergic ointments scopolamine, glycopyrolate.


Topical anti-perspirants 


Topical α agonist (clonidine)


Botulinum toxin injections


Botulinum toxin provides the longest period of symptom relief with the lowest complications.


No cure exists, but for permanent treatment, reconstructive surgery required.