What Is It? 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. Symptoms of cluster headache
include: A bloodshot or tearing eye on the affected side Smaller
pupil or droopy eyelid on the a