Characteristics of a typical cluster headache include:

Pain remains on the same side during a series.

Pain is localized behind the eye or in the eye region and may radiate to the forehead, temple, nose, cheek or upper gum on that side.

Nasal congestion and tearing of the eye is on the same side as the pain.

Excessive sweating

Skin may become flushed on that side.

Often occur in the early morning or at night during REM sleep, the deepest sleep cycle.

Cluster headaches are not associated with gastrointestinal disturbances or sensitivity found in other vascular headaches, such as migraine.

Substances that cause blood vessel swelling can provoke an attack during a series, such as nitroglycerin or histamine, smoking or minimal amounts of alcohol. The blood vessels, however, are not sensitive to these substances during headache-free periods. Unlike migraines, hormonal influences in women do not appear to be a factor in cluster headaches.

Source: National Headache Foundation

Resources

The New England Center for Headache in Stamford, Conn., is one of the leading centers in the United States conducting research into this condition. You can find out more at www.headachenech.com. To learn about clinical trials under way there, call 1-203-322-2748.

www.clusterheadaches.com and its nonprofit site operated by Organization for Understanding Cluster Headaches (O.U.C.H.), www.clusterheadaches.org. You can find information about the July convention at www.clusterheadaches.org/conventions/2004/index.htm

First Published: June 8, 2004, 4:00 a.m.