As a result of severance and inappropriate regeneration, the parasympathetic nerve fibers may switch course to a sympathetic response, resulting in "gustatory sweating" or sweating in the anticipation of eating, instead of the normal salivary 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 salivation. It can also include discharge from the nose when smelling certain food. Rarely, Freys syndrome can result from causes other than surgery, including accidental trauma, local infections, sympathetic dysfunction and pathologic lesions within the parotid gland. An example of such rare trauma or localized infection can be seen in situations where a hair follicle has become ingrown, and is causing trauma or localized infection near or over one of the branches of the auriculotemporal nerve. Diagnosis
Diagnosis is made based on clinical signs and symptoms and a starch-iodine test, also known as the Minor test. The affected area of the face is painted with iodine which is allowed to dry, then dry corn starch is applied to the face. The starch turns blue on exposure to iodine in the presence of sweat.
Treatments
Injection of botulinum toxin A
Surgical transection of the nerve fibers (a temporary treatment)
Application of an ointment containing an anticholinergic drug such as scopolamineCochrane reviews of interventions to either prevent or treat Freys syndrome have found little or no evidence to support their effectiveness or safety, and conclude that further clinical trials are needed. Epidemiology
The condition is rare, although the exact incidence is unknown.The disorder most often occurs as a complication of the surgical removal of a parotid gland (parotidectomy). The percentage of individuals who develop Frey syndrome after a parotidectomy is controversial and reported estimates range from 30 to 50 percent. In follow-up examinations, approximately 15 percent of affected individuals rated their symptoms as severe. Frey syndrome affects males and females in equal numbers. History
It is named after Łucja Frey-Gottesman. The disorder was first reported in medical literature by Baillarger in 1853. A neurologist from Poland, Dr. Lucja Frey, provided a detailed assessment of the disorder and coined the term "auriculotemporal syndrome" in 1923. References


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