| Risk Factors Migraine is a type of recurring headache. It
involves nerves and brain chemicals. Other sensations (eg,
auras) may come before a migraine headache. There are two types
of migraines: - Occurring with an aura (formerly called
"classic") - Occurring without an aura (formerly called
"common") Migraine may happen several times a week or once every
couple of years. They can be so severe that they interfere with
the ability to work and carry on normal activities. While the
precise cause is not known, many potential triggers have been
identified. Common triggers include: - Environmental triggers
(eg, odors, bright lights) - Dietary triggers (eg, alcohol) -
Certain medicines - Changes in sleep patterns - Physiologic
changes (eg, menstruation, puberty) - Weather changes A trigger
sets the process in motion. It is possible that the nervous
system reacts to the trigger by conducting electrical activity.
This spreads across the brain. It leads to the release of brain
chemicals, which help regulate pain. Fac