Signs and Symptoms - Erythema (redness or flushing) and sweating in the cutaneous distribution of the auriculotemporal nerve - Pain in the same area, often burning in nature - Numbness or other altered sensations between attacks of pain - Gustatory neuralgia may be present - Discharge from the nose when smelling certain food

Causes - Complication of surgeries near the parotid gland or injury to the auriculotemporal nerve - Regeneration or nerve sprouting after endoscopic thoracic sympathectomy - Accidental trauma, local infections, sympathetic dysfunction, or pathologic lesions within the parotid gland - Ingrown hair follicle causing trauma or localised infection near the auriculotemporal nerve - Switching of parasympathetic nerve fibers to a sympathetic response

Diagnosis - Clinical signs and symptoms - Starch-iodine test (Minor test) where iodine is applied to the face and starch turns blue in the presence of sweat - No personal pronouns in bullet list items

Treatments - Injection of botulinum toxin A - Surgical transection of the nerve fibers (temporary treatment) - Application of an ointment containing an anticholinergic drug - Limited evidence supporting the effectiveness or safety of interventions - Need for further clinical trials

Epidemiology - Rare condition with unknown incidence - Often occurs as a complication of parotidectomy - Estimates suggest 30-50% of individuals develop Frey syndrome after parotidectomy - Approximately 15% of affected individuals rate their symptoms as severe - Affects males and females equally