Frey Syndrome

Frey syndrome, also known as Baillarger’s syndrome, auriculotemporal syndrome, Dupuy syndrome, or gustatory hyperhidrosis, represents aberrant reinnervation following injury to the auriculotemporal nerve. The auriculotemporal nerve, a branch of the trigeminal nerve, consists of parasympathetic fibers that signal the parotid gland to produce saliva and sympathetic fibers that innervate the sweat glands of the face and scalp. When an insult to the parasympathetic and sympathetic nerve fibers of the auriculotemporal nerve in the parotid region occurs, the resulting aberrant regeneration of post-ganglionic parasympathetic nerve fibers (responsible for salivary secretion) along the pre-existing sympathetic pathways to the vessels and sweat glands of the skin leads to the development of Frey syndrome. Patients with Frey syndrome often present with facial warmth, flushing, and sweating in the territory of the auriculotemporal nerve overlying the parotid gland, which may include the preauricular skin, the temporal skin, the scalp, and the temporomandibular joint region. Symptoms occur during meals, especially with spicy and sour foods. Frey syndrome most commonly arises as a complication of parotidectomy. Still, it can also be associated with submandibular gland surgery, repair of mandibular fractures, temporomandibular joint injury, neck lymph node dissection, infection, and trauma to the parotid region. Dr. Jules Baillarger first reported the phenomenon in 1853, describing 2 patients who underwent incision and drainage for parotid abscesses. The patients later developed facial sweating during meals. At that time, he misinterpreted the facial fluid as saliva overflowing through the skin due to a blocked Stenson’s duct. Previously, Dupuy described gustatory sweating over the cheek area as being related to experimental sectioning of cervical sympathetic nerves in horses around 1816. Then, in 1897, Weber described bilateral gustatory sweating and flushing in a patient who had undergone bilateral parotid abscess drainage, the first reported case of bilateral Frey syndrome. It was not until 1923 that the first accurate description of this phenomenon was provided by Dr. Lucja Frey, a Polish physician and 1 of the first female academic neurologists in Europe. She described a 25-year-old female who sustained a gunshot wound to the parotid region and subsequently developed facial flushing and sweating 5 months afterward. She accurately identified the autonomic innervation of the parotid gland and the auriculotemporal nerve as the link between gustatory stimulation and facial sweat production. In 1927, Dr. Andre Thomas theorized that the pathophysiology of the disease involved aberrant nerve regeneration. Five years later, Dr. Peter Bassoe reported the first case of Frey syndrome after a parotidectomy, which has since become the most common cause of the condition.