> The name cluster headache describes attacks of excruciating, one-sided pain that is usually located around one eye

> Cluster headaches are less common than migraine, and the headaches are of shorter duration, lasting 15 minutes to 3 hours

> Attacks usually occur in a series, or “clusters” of 1 – 8 headaches per day over a period of several weeks to months, separated by headache-free intervals that may last months or years. However, about 10-15% of patients have chronic symptoms without remissions.

> The attacks are associated with one or more of the following, all of which occur on one side and on the same side of the head: red and/or tearing of the eye, nasal congestion, runny nose, forehead and facial sweating, contraction of the pupil, drooping eyelid, eyelid swelling

> Most patients are restless or agitated during an attack and are usually unable to lie down. It is common to see this patient pace the floor during an attack.

> During a cluster period, attacks occur regularly and may be provoked by small amounts of alcohol or nitroglycerine

> Cluster headaches often occur at night

> Age at onset is usually 20-40 years old

> Cluster headaches are 3 – 4 times more prevalent in men than in women

> Preventive management of cluster headaches involves medications taken at the beginning of the cluster period and daily until it resolves

> Acute treatment is used to control the pain and other symptoms associated with a cluster attack