Cluster headaches are recurring headaches whose attacks last 15 minutes to three hours and several times a day for weeks or even months and years. The pain arrives with little, if any, warning and it has been described as the most severe and intense of any headache type, with severe pain on one side of the head, usually in and around the eye. The pain is so intense that sufferers have considered suicide during attacks. It is associated with tearing, red eye, stuffy nose, facial sweating or other changes in the eye. Clusters often occur during spring or autumn and thus are often incorrectly associated with allergies.
In one study, headache sufferers got substantial relief when a capsaicin solution (the active ingredient in red pepper) was applied to the nostril or temple on the side of the head where the headache occurred. Capsaicin cream is sold over the counter for the relief of chronic pain from conditions including shingles, diabetic neuropathy and arthritis.
Cluster headaches affect about 1% of the population, usually men between the ages of 20 and 45 (about 80% of the victims are men). Around 20% of patients seem not to respond to any treatments; surgery may be recommended. Triggers include alcohol, smoking, sleep deprivation, excessive exercise, volatile chemicals and changes in barometric pressure.