As many as two-thirds of those affected by migraines may also experience a condition called cutaneous allodynia. Cutaneous allodynia is skin sensitivity and pain so severe that everyday activities like brushing your hair or wearing jewelry can cause pain.

"The phenomenon of cutaneous allodynia seems to be correlated to true migraine," said headache expert Dr. Bruce Silverman, a neurologist at Providence Hospital and Medical Centers in Southfield, Mich. "For those with migraine and cutaneous allodynia, the idea of treating prior to the onset of symptoms may offer a greater response."

To assess the prevalence of cutaneous allodynia, researchers led by Dr. Marcelo Bigal, of Albert Einstein College of Medicine, New York City, surveyed almost 17,000 people who experienced headaches. Their questionnaires asked about the type of headaches suffered, how often, whether or not their quality of life was affected, whether or not they suffered from depression, or if they had any other illnesses that might cause pain. Survey participants were also asked to complete the allodynia symptom checklist (ASC), an assessment tool previously designed by the study's authors.

The study, which is in the April 22 issue of the journal Neurology, found that almost 12,000 people reported suffering from migraines. Another 1,491 had headaches that were probably migraines, and 3,345 experienced other types of headaches, such as tension headaches.

Of those who reported having chronic migraines �?daily headaches �?68 percent also experienced cutaneous allodynia. In those with episodic migraines, 63 percent also experienced the condition. Just 42 percent of those with suspected migraine reported cutaneous allodynia, and about 37 percent of those with other types of headaches reported allodynia, as well.

In people with migraine, cutaneous allodynia was more common in women, in those who had headaches more often, in people with a higher body mass index, and in those disabled or depressed.

The study was sponsored by the National Headache Foundation through a grant from Ortho-McNeil Neurologics Inc., a pharmaceutical company that makes Axert, a drug that's part of a class of medications known as triptans that are used to treat migraine in its acute stages, and Topamax, a preventive migraine medication. Bigal is currently an employee of Merck & Co., the maker of Maxalt, another triptan medication.

"This study highlights the importance of early treatment in migraine," according to Silverman, who was not involved in the research. He explained that by the time someone is experiencing cutaneous allodynia, triptan medications tend not to be as effective as when they're taken early on in a migraine.

"When you delay treating and don't take a triptan right away, it doesn't work as well. It gets harder and harder to get rid of," agreed Dr. Keith Siller, an assistant professor of neurology at New York University Medical Center in New York City.

He said this study's findings might help differentiate true migraines from other types of headaches, such as tension headaches, but that he wasn't familiar with the allodynia symptom checklist used in this study.

If you've been diagnosed with migraine and haven't found relief, Siller suggested seeing a neurologist, because there are preventive medications available.