Medical Health Encyclopedia

Evidence for genetic factors has been weak, but there is a growing body of research suggesting a family history in about 5% to 10% of patients. Some evidence suggests that cluster headaches in women may be more likely to be genetically based, particularly when they first occur at younger ages.

High Iron Stores

Cluster headaches were also reported in two cousins with hereditary hemochromatosis, a disease characterized by the buildup of iron. Lowering iron levels in one of the cousins brought headache relief. Although this study does not prove that high iron levels cause cluster headaches, iron deposits in the brainstem may affect pain centers.

History of Migraine

A 2002 study reported that 26% of cluster headache sufferers also had a personal history of migraines and 33% had a family history of this headache. Most studies have reported that about 15% of patients have both kinds. (It should be noted, however, that the study noted here had a higher-than average number of women in the study. Also cluster headache is much less common than migraine.)

Head Injury

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Head injury may also increase the risk of cluster headaches. In one study, over 13% of patients reported a history of a head injury that caused loss of consciousness and nearly a quarter had experienced a head injury without loss of consciousness.

Sleep Apnea and Other Sleep Disorders

Cluster headaches tend occur during specific sleep stages and have been associated with several sleep disorders, including narcolepsy, insomnia, and sleep apnea.

Sleep apnea, a disorder in which a person stops breathing during the night, perhaps hundreds of times, is of particular interest. Studies have reported sleep apnea in 30% to 80% of cluster headache patients. One study suggested that in some people apneas may trigger cluster headache during the first few hours of sleep, making patients susceptible to follow-up attacks during the following midday to afternoon periods. Treating patients who have both disorders with a device called CPAP, which opens the airways, may help improve both conditions. Note: Although sleep apnea inevitably causes daytime sleepiness, most people who have it are not even aware of it.