cluster headache
A specific type of severe headache that occurs in cyclical patterns or clusters.
Cluster headaches cause intense pain behind the eye.
He suffers from cluster headaches.
片頭痛 (migraine) is a different type of headache, often with throbbing pain on one side, while 群発性頭痛 occurs in clusters with severe, piercing pain.
Compound of 群発 (cluster occurrence) + 性 (nature) + 頭痛 (headache). The term is a direct medical translation of the English 'cluster headache'.