A migraine diary may help you pinpoint -- and avoid -- headache triggers, a neurologist says.

About 12 percent of people in the United States suffer from migraines, according to the Migraine Research Foundation.

"A migraine can be debilitating and can impact daily activities, your family and social life. Unfortunately, migraine often goes undiagnosed and undertreated," said Dr. Sait Ashina. He's a neurologist and headache specialist at Beth Israel Deaconess Medical Center in Boston.

While the exact causes of migraines remain unknown, doctors can help patients identify their triggers.

"Triggers are what can set off the symptoms of a migraine headache, which is different than the mechanisms of the head pain," Ashina explained in a hospital news release. "Triggers are usually individualized -- what could bring on a migraine in one person could not be the case in another person."

Keeping a migraine diary can help uncover headache triggers, Ashina said. Common ones include caffeine; fasting, dieting and dehydration; weather changes; lack of sleep; odors; bright or fluorescent light; and hormonal changes, especially for women.

"Your doctor is going to want to know what you did or ate or how you felt right before a migraine attack," Ashina said. "By tracking these occurrences and any details you remember ahead of time, your doctor will be able to find patterns that will guide an individualized treatment plan."

List each migraine in the diary, when it happened, how long it lasted and possible triggers.

The American Headache Society offers headache diary resources, as do several mobile apps.

"Your headache diary will be your doctor's best resource for avoiding any of these triggers," Ashina said. "By controlling what you can, you may reduce the frequency and severity of your headaches."