Cluster headaches are very intense headaches. They usually start in the area around one eye, then spread to nearby areas of the face. Each headache lasts about a half-hour to three hours. Episodes can occur several times over 24 hours (in clusters). This happens daily, lasting several weeks to months.
Most cluster headaches occur at night. This condition affects men much more frequently than women. Some people discover they have "triggers" that start the headache, such as:
Certain foods, especially those with high amounts of nitrites (bacon for example)
Hot weather or hot showers and baths
On average, people experience one to three headache episodes daily for four to eight weeks. Once a cluster of episodes ends, the person may remain headache-free for months or years.
The cause of cluster headaches is unknown. They may be related to a temporary imbalance of brain chemicals.