Cluster headache is an excruciating type of vascular headache.
It is similar to migraine, but shorter in duration, more frequently occurring, and often more severe. It effects men more than women, and is much more rare than migraine. Usually cluster headache starts out around or behind the eye. Attacks arrive in clusters, lasting weeks to months, with months or years between headache cycles. Sometimes cluster headaches become chronic, in which case they do not go into a remission with breaks between cycles.