During the headache attack however, cluster and migraine patients might have some abnormal clinical findings, and many patients with tension-type headache have demonstrable tightness in the cervical muscles, with limitation of neck motion, scalp tenderness, or both.
Secondary headaches are usually of recent onset and associated with abnormalities found on clinical examination.
Because the three primary headache syndromes tend to begin in persons younger than 50 years, anyone older than 50 years with a recent onset of headache should have a thorough examination and testing to look for an underlying cause.
How this septal defect is associated with causing or triggering migraine with aura is unknown.
Double-blind studies of catheter closure (or a sham procedure) of patent foramen ovales in migraineurs have been inconclusive.
Migraine is three times more common in female patients.
The prevalence of cluster headache is less certain.
Migraine and cluster headaches are believed to initially begin in the brain as a neurologic dysfunction, with subsequent involvement of the trigeminal nerve and cranial vessels.
In cluster headache, most, but not all, sufferers have overactivity of the parasympathetic nervous system.
Should an abnormality be found on testing, by definition, it most likely is not the cause of the headache.
Similarly, the physical and neurologic examinations are also usually normal, but any abnormalities found are not related to the primary headache.
Many causes of headache have been described in the medical literature.
In 1988, the International Headache Society published a long, detailed classification of headache, which has proved helpful for research purposes because it has led to more reproducible and reliable studies in the field of headache.
This classification was updated and revised in 2004.