Cluster headaches are recurring headaches that occur in groups or cycles. The headaches appear suddenly and cause severe, debilitating pain on one side of the head, along with a watery eye and nasal congestion on the affected side of the head.
The cause of cluster headaches is unknown. Although there is no cure for cluster headaches, medicines can reduce the frequency and duration of the painful headaches.
eMedicineHealth Medical Reference from Healthwise
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