The word "migraine" comes from the Greek
word meaning "half of the skull" - a logical designation, since this
type of headache is often confined to one side of the head.
Migraine and the more painful cluster headache are called vascular
headaches because they are believed to be caused by the blood vessels
(vasculature) in the head contracting, then expanding (dilating),
causing pain to the nerve endings of the head. There are a
number of factors contributing to a vascular headache, they are,
stress, certain foods (eg. processed meats with nitrates, chocolate,
aged cheese, foods with monosodium glutamate), alcohol (especially red
wine), irregular or excessive sleeping patterns, excessive use of
painkillers, tobacco, some prescription drugs and withdrawal from
caffeine and some drugs.
The "Classic" migraine consists of "prodromal"
(early) symptoms or aura experienced by the person prior to the onset
of the headache, for example, flashing lights, blind spots or
flickering vision followed by an initially throbbing or pulsating
headache to one side of the head which later becomes steady or dull.
Other symptoms include nausea, vomiting, or dizziness. However,
most migraines do not occur in the classic form, and experts
increasingly use the phrase migraine variants to cover other kinds of
headaches (and other associated symptoms such as nausea and vomiting)
that do not fit this classic description. For example, cluster
headaches are so-called because they tend to occur in clusters over a
period of days, weeks, or months and are probably part of the migraine
family. Those common or "simple" migraine headaches usually
cause pain throughout the head and not part of it and are not
accompanied with an aura. Cluster headaches produce excruciating
pain around one eye and recur repetitively over days, weeks, or
months, then disappear for a period of time, only to occur again.
It should also be stressed that some
headaches formerly labeled as sinus headaches, because they were
accompanied by nasal stuffiness and pain in the sinus area, are now
being recognized as migraine headaches accompanied by tear formation
and nasal discharge. The common underlying bond for all the
headaches labeled "migraine" is a role played by the blood vessels of
the neck and head. There is strong evidence that the early
symptoms are usually related to constriction of these vessels and that
the actual headache occurs when the vessels subsequently expand.
The exact reasons for these blood vessel changes are not certain,
though current interest is focused on the role of platelets and
chemicals (like serotonin) which act on blood vessels.