Episodic cluster headache with suspected giant cell arteritis, sinusitis-related headache, and dietary triggers: a case report.

Background: Cluster headache is a primary trigeminal autonomic cephalalgia characterized by severe, strictly unilateral orbital/periorbital pain with ipsilateral autonomic features. It is rare for a patient with cluster headache to have coexisting multiple headache disorders and experience unusual triggers. Case presentation: A 53-year-old male with a 14-year history of episodic cluster headache presented with his third cluster episode. He exhibited strictly unilateral left orbital/periorbital/temporal drilling pain [Visual Analogue Scale (VAS) 9-10/10], ipsilateral conjunctival injection, lacrimation, rhinorrhea, and agitation. Notably, during the second episode (2015), left maxillary sinusitis was identified and surgically treated, leading to immediate and complete headache resolution. During the current episode, physical examination revealed left temporal artery nodularity and tenderness-raising suspicion of giant cell arteritis. However, the erythrocyte sedimentation rate and C-reactive protein levels were within the normal range. Brain MRI/MRA revealed only nonspecific white matter changes, along with suspected wall thickening of the left superficial temporal artery. The patient declined temporal artery ultrasound, high-resolution MRI, and biopsy. In accordance with clinical guidelines, the patient was administered comprehensive treatment for cluster headache. Given the suspicion of giant cell arteritis, empirical prednisone was also initiated at a dose of 1 mg/kg/day. By day 3 of treatment, attack frequency had reduced from daily to 3-4 times per week, pain intensity decreased from VAS 10/10 to 3-6/10, attacks resolved within 30 min either spontaneously or after zolmitriptan, and temporal artery nodules had markedly diminished. Interestingly, during follow-up, the patient reported that ingestion of soy sauce or vinegar consistently triggered an unusual throat discomfort followed by headache within 30 min, whereas avoidance of these substances resulted in no attacks. The patient's strict avoidance of soy sauce and vinegar led to a marked reduction in headache frequency over a short period, ultimately resulting in a complete absence of headache episodes. He remains under follow-up. Conclusion: This case highlights an unusual concurrence of episodic cluster headache with suspected giant cell arteritis and possible sinusitis-related headache in a single patient. The potential role of soy sauce and vinegar as triggers for cluster headache warrants further validation with extended follow-up and a larger case series.