Epidemiology of cluster headache.

Cluster headache was first described over 300 years ago, but in the last century our knowledge of the disorder has exploded through both clinical observation and epidemiological data. Although some of the data are conflicting and more need to be obtained, much is known about the disorder. This article reviews the data to date on the prevalence and incidence of the disorder, population differences including gender and race, genetics, comorbid conditions, risk factors for development of the disorder, prognosis, and socioeconomic burden.