Temperature-Related Atypical First-Bite Syndrome: A Rare Case Report

Zuntai Li^1,2*Ke Zhang^3,4Yifan Dong¹Zihui Wang¹Chunxia Zhang¹Long Su^3,4*Bo Zhao^3*

• ¹Department of Stomatology, Tianjin First Central Hospital, Tianjin, China
• ²NHC Key Laboratory of Critical Care Medicine, Tianjin, China
• ³Department of ophthalmology, The Second Hospital of Tianjin Medical University, Tianjin, China
• ⁴tianjin institute of orbital disease, Tianjin, China

First bite syndrome (FBS) manifests is characterized by severe parotid pain triggered by the first bite of food, with or without muscle spasms. The pain typically diminishes with subsequent bites. We report a case of 32-year-old male with Marcus-Gunn syndrome (30-year history), no prior head or neck surgery, tumors, infections, or temporomandibular joint disease. Since age of 15, he experiences bilateral parotid pain and spasms exclusively upon consuming ice cream in high ambient temperatures post-summer exercise. Symptoms resolve spontaneously within 30 seconds and persist despite trials of heat therapy, massage, and physiotherapy. While approximately 42% of FBS cases have identifiable etiology, others implicate aberrant activity in the auriculotemporal, greater auricular, or cervical sympathetic nerves. In this patient, symptoms occur only with cold food ingestion in hot environments, suggesting involvement of the trigeminal nerve's mandibular branch in oral thermosensation. To our knowledge, this is the first reported case linking FBS symptoms to temperature sensation.