Cluster headaches are rare, extremely painful and debilitating headaches that occur in groups or clusters. Signs and symptoms Cluster headache sufferers typically experience very severe headaches of a piercing quality near one eye or temple that last for fifteen minutes to three hours. The headaches are usually unilateral and occasionally change sides. Cluster headaches are frequently associated with drooping eyelids, conjunctival injection (which results in red, watery eyes), tearing, ...
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