Abstract
Patient: A 59-year-old man had experienced intense left facial pain at the beginning of and after meals. No apparent abnormal finding was detected by the clinical examination, panoramic radiography, MRI, ultrasonography except for tenderness of the left parotid gland and submandibular gland. We diagnosed idiopathic first bite syndrome （FBS）. At the same time, we found hyperglycemia in his laboratory data. He was referred to a diabetes specialist and underwent treatment for diabetes. The beginning of and after meals pain improved as the decrease of blood glucose level.
Discussion: In this case, pain at the beginning of and after meals improved significantly after the diabetes treatment, and the severe postprandial pain disappeared. Although idiopathic FBS has been suggested to be associated with diabetes, the experience of this case indicates that hyperglycemia may be strongly involved in the pain of idiopathic FBS.
Conclusions: When diagnosing idiopathic FBS, it may be necessary to confirm the history of diabetes and laboratory data.
