What Triggers Cluster Headaches?
The season is the most common trigger for cluster headaches, which often occur in the spring or autumn. Due to their seasonal nature, cluster headaches are often mistakenly associated with allergies or business stress. The seasonal nature of cluster headaches most likely results from stimulation or activation of the hypothalamus (see above).
Cluster headaches are also common in people who smoke and drink alcohol excessively. During a cluster period, the sufferer is more sensitive to the action of alcohol and nicotine, and minimal amounts of alcohol can trigger the headaches. During headache-free periods, the person can consume alcohol without provoking a headache.
What Are the Symptoms of a Cluster Headache?
Cluster headaches generally reach their full force within five or ten minutes after onset. The attacks are usually very similar, varying only slightly from one attack to another.
- Type of pain: The pain of cluster headache is almost always one-sided, and during a headache period, the pain remains on the same side. When a new headache period starts, it rarely occurs on the opposite side.
- Severity/intensity of pain: The pain of a cluster headache is generally very intense and severe and is often described as having a burning or piercing quality. It may be throbbing or constant. The pain is so intense that most cluster headache sufferers cannot sit still and will often pace during an attack.
- Location of pain: The pain is located behind one eye or in the eye region, without changing sides. It may radiate to the forehead, temple, nose, cheek, or upper gum on the affected side. The scalp may be tender, and the pulsing in the arteries often can be felt.
- Duration of pain: The pain of a cluster headache lasts a short time, generally 30 to 90 minutes. It may, however, last from 15 minutes to three hours. The headache will disappear only to recur later that day. Typically, in between attacks, people with cluster headaches are headache-free.
- Frequency of headaches: Most sufferers get one to three headaches per day during a cluster period (the time when the headache sufferer is experiencing daily attacks). They occur very regularly, generally at the same time each day, and have been called "alarm clock headaches," because they often awaken the person at the same time during the night.
Most cluster sufferers (80%-90%) have episodic cluster headaches that occur in periods lasting seven days to one year, separated by pain-free episodes lasting 14 days or more.
In about 20% of people with cluster headaches, the attacks may be chronic, meaning there are less than 14 headache-free days per year.
Cluster headaches are not typically associated with nausea or vomiting. It is possible for someone with cluster headaches to also suffer from migraines.