First-bite syndrome after parapharyngeal surgery for cervical schwannoma.

Background: First-bite syndrome (FBS) is a rare complication that occurs after patients undergo parapharyngeal space surgery. Characteristically, inadvertent ablation of the parotid gland's sympathetic innervation results in the development of severe parotid gland-area pain at the first bite of food.
Case Description: The authors evaluated a patient who underwent parapharyngeal surgery for cervical schwannoma. This surgery involved the sympathetic chain's superior cervical ganglion (SCG). With destruction of the SCG, the patient developed FBS and Horner syndrome.
Conclusion and Clinical Implications: Destruction of the SCG or the sympathetic postganglionic supply to the parotid gland causes severe parotid pain when food is first introduced into the mouth. The absence of discomfort during mechanical joint movements helps dentists differentiate this pain from myofascial pain or pain caused by temporomandibular dysfunction. The frequent presence of Horner syndrome also facilitates diagnosis.