Cluster headaches, previously known as migrainous neuralgia, are a unique type of headache syndrome. There are two primary forms: episodic and chronic.Episodic cluster headaches are the most prevalent form. Individuals experience 1-3 brief episodes of intense pain around the eyes daily, with these attacks occurring over a period of 1-2 months, followed by a pain-free interval. This remission period typically lasts about a year.Chronic cluster headaches, on the other hand, are marked by the lack of extended remission periods. They can either begin without any previous episodic headaches or develop after years of episodic patterns.The episodic and chronic forms can transition into one another, suggesting they may simply be different manifestations of the same condition. Despite some similarities in underlying mechanisms, cluster headaches are distinct from migraines. For instance, propranolol is effective for migraines but not for cluster headaches, while certain treatments work for cluster headaches but not for migraines.Cluster headaches have been referred to by various confusing names, such as erythroprosopalgia, cephalalgia, Raeder's syndrome, sphenopalatine neuralgia, and vidian neuralgia.