Frey's syndrome

Frey's syndrome (also known as Baillarger’s syndrome, Dupuy’s syndrome, Auriculotemporal syndrome or Frey-Baillarger syndrome) is a rare neurological disorder resulting from damage to or near the parotid glands responsible for making saliva, and from damage to the auricotemporal nerve often from surgery.

The symptoms of Frey's syndrome are redness and sweating on the cheek area adjacent to the ear (see focal hyperhidrosis). They can appear when the affected person eats, sees, dreams, thinks about or talks about certain kinds of food which produce strong salivation. Observing sweating in the region after eating a lemon wedge may be diagnostic.

Signs and symptoms
Signs and symptoms include erythema (redness/flushing) and sweating in the cutaneous distribution of the auriculotemporal nerve, usually in response to gustatory stimuli. There is sometimes pain in the same area, often of a burning nature. Between attacks of pain there is sometimes numbness or other alterred sensations (anesthesia or paresthesia). This is sometimes termed "gustatory neuralgia".

Causes
Frey's syndrome often results as a side effect of surgeries of or near the parotid gland or due to injury to the auriculotemporal nerve, which passes through the parotid gland in the early part of its course. The Auriculotemporal branch of the Trigeminal nerve carries parasympathetic fibers to the sweat glands of the scalp and the parotid gland. As a result of severance and inappropriate regeneration, the parasympathetic nerve fibers may switch course, resulting in "gustatory Sweating" or sweating in the anticipation of eating, instead of the normal salivatory response. It is often seen with patients who have undergone endoscopic thoracic sympathectomy, a surgical procedure wherein part of the sympathetic trunk is cut or clamped to treat sweating of the hands or blushing. The subsequent regeneration or nerve sprouting leads to abnormal sweating and salivating. It can also include discharge from the nose when smelling certain food.

Rarely, Frey's syndrome can result from causes other than surgery, including accidental trauma,local infections, sympathetic dysfunction and pathologic lesions within the parotid gland.

Treatments
There is no effective treatment, but various options are described:
 * Injection of Botulinum Toxin A
 * Surgical transection of the nerve fibers (only a temporary treatment)
 * Application of an ointment containing an anticholinergic drug such as scopolamine

Epidemiology
The condition is rare.

History
It is named after Łucja Frey-Gottesman.