There are dozens of headache disorders, but they break down into three classification groups: Tension-Type, Migraine, and Trigeminal Autonomic Cephalalgia (TAC). Cluster headaches are the most commn of the TACs, and they are estimated to affect .1 percent of the population (a similar percentage to multiple sclerosis).
Most Headache Disorders share some common symptoms, which is part of what makes diagnosis so complex. However, the following diagnostic criteria are specific to Cluster Headache and can make it much easier to identify patients who are experiencing this particular type of disorder:
Cluster headache attacks only occur on one side of the head. While they may switch sides (which is rare), they affect just one side at a time.
HIGHLY SPECIFIC, LOCALIZED PAIN
Patients with cluster headaches often describe the pain in similar ways, such as a “hot poker,” “icepick,” or “dagger” being driven in and out of their head on one side near the temple and surrounding the eye.
The pressure and stabbing pain behind and around the eye has caused at least one patient to pull out their eyeball, and others have resorted to suicide to stop the attack, earning Cluster Headaches the nickname of “Suicide Headaches.”
FREQUENCY AND DURATION
Each Cluster Headache attack may last anywhere from 15-180 minutes, and can occur once every other day or up to eight times a day according to the International Headache Society, although some cluster patients report up to 12 a day. This frequency happens more than 50 percent of the time the patient has active cluster headaches.
Autonomic symptoms are one of the most notable differences between TAC and other primary headache disorders. Cluster headaches are always accompanied by at least one of these features, which also only occur on the side of the head experiencing the lancing pain:
- Red or tearing eye
- Nasal congestion or running nose
- Swollen eyelid (oedema)
- Forehead and facial sweating or flushing
- Ear fullness (which seems to be more prevalent in women with cluster headache)
- Drooping upper eyelid
- Pupil constriction
Cluster headache patients have immense difficulty sitting still. They will pace, rock back and forth, scream, and hit themselves. There have been instances of cluster patients being involuntarily institutionalized because their behavior during an attack looks like a psychotic break. While migraine patients prefer a quiet, dark room, cluster patients would sooner want a loud rock concert—anything to distract from the pain.
A Cluster Headache diagnosis requires one to have at least five attacks that meet the criteria listed above, which is not better described by another headache disorder. For decades, it was thought that mainly, if not only, men have cluster headaches, but we now know women and children as young as eight can have cluster. The male-to-female ratio seems to be 2:1 but varies in each research study. There’s also a “probable cluster headache” diagnosis for those who fit all but one of the criteria.