Abstract

•The International Classification of Sleep Disorders recognizes four types of headaches related to sleep: cluster headache, hypnic headache, chronic paroxysmal hemicrania, and migraine.1 The prevalence of cluster headaches is 0.1% and its etiology is unknown.2 More men than women suffer from cluster headaches and patients typically exhibit wakefulness, agitation, and a desire to pace during paroxysmal bouts which are characterized by multiple headaches that remit and recur over the course of several hours or days.3,4 Typically, a headache would last from 15 minutes to 3 hours, resolve spontaneously, and then recur, giving the condition its name of “cluster” headache. Cluster attacks are excruciatingly painful and differ from other types of headache in that the pain is periorbital, unilateral, and the episodes typically involve rhinitis, drooping eyelids, and lacrimation. People experiencing a cluster headache find no relief in sleep and may even prefer to pace or stand up.

•Unlike other sleep-related headaches, cluster headaches have a clear diurnal relationship (many patients arise with the headache) and seasonality, such that patients may have months of remission.5 Some patients develop chronic cluster headaches which do not have such periods of remission. Headaches in general are associated with poor quality sleep,6 but the association is quite pronounced in cluster headaches.  People who suffer from any types of headache are also more likely to report symptoms associated with poor sleep, such as daytime fatigue and insomnia.7,8 It has been speculated that cluster headaches may be a manifestation of a sleep disorder or that more complex sleep-related mechanisms are involved.9

•The purpose of this review is to examine the literature on cluster headaches and their relationship to sleep to present the current understanding by the medical community.