Ciliary neuralgia, more commonly recognized today as a cluster headache, is a unique headache syndrome. Cluster headaches manifest in two primary clinical forms: episodic and chronic.Episodic cluster headaches are the most prevalent, characterized by 1-3 brief episodes of eye pain each day. These attacks occur in clusters lasting 1-2 months, followed by a pain-free period known as remission. On average, this remission lasts about a year.Chronic cluster headaches, on the other hand, lack these extended pain-free intervals. They can either begin without a previous history of cluster headaches or develop several years after an episodic pattern has been established.Episodic and chronic cluster headaches can evolve into one another, suggesting they may simply be different expressions of the same underlying condition. Although some mechanisms might overlap, cluster headaches are distinct from migraines. For instance, propranolol is effective for migraines but not for cluster headaches, while other treatments benefit cluster headaches but not migraines.Cluster headaches have been referred to by various other names, such as erythroprosopalgia, cephalalgia, Raeder's syndrome, sphenopalatine neuralgia, and vidian neuralgia, adding to the confusion surrounding the terminology.