About 1 out of 8 Americans has migraines. They usually begin during the teenage years. After puberty, migraines are more likely to affect girls and women.
Experts still aren't sure what causes these headaches. But they seem to involve a wave of unusual activity in brain nerve cells, along with changes in blood flow in the brain.
Though migraines can trigger severe pain in the head, they aren't simply headaches. They often also cause other uncomfortable symptoms, such as:
Unusual sensitivity to light, noises, and smells
A migraine episode can be a complicated event, with symptoms that change over hours or even days. Migraines tend to progress through several stages:
Prodromal phase before the migraine
Postdromal phase after the migraine
Prodromal Phase: Early Warning Signs
Several hours before the migraine begins -- and sometimes even the day before -- many people with migraines notice unusual sensations. They may feel:
Either unusually energetic and excitable or depressed
Cravings for certain foods
Sleepy, with frequent yawning
Need to urinate more
In some cases, these symptoms before the headache can help health care providers diagnose the problem as migraines.
Aura Phase: Strange Sensations Arise
About 1 in 5 people with migraine develop an "aura" that begins before the headache or starts along with it. An aura may not occur with every headache.
An aura can include:
Changes in vision. Often visual symptoms begin first during the aura phase. During a migraine you may experience these vision changes:
A flickering, jagged arc of light. This may take a complicated shape. It usually appears on the left or right side of your vision. Over a few minutes, it may spread in size.
An area of vision loss. This problem -- combined with the flickering lights -- can make driving or focusing your eyes on small objects difficult.
"See" images from the past or hallucinations.
These symptoms may continue to grow more severe over the next several minutes.
Skin sensations. This part of the aura may cause tingling or "pins and needles" sensations in the body. It may also cause numbness. These feelings often affect the face and hands but can spread out across the body. The sensations may continue to expand over the next several minutes.
Language problems. During the aura phase of a migraine, you may have trouble communicating with others. Symptoms may include:
Difficulty expressing thoughts while speaking or writing