There appears to be general agreement however that a key element is changes in the blood flow within the brain that become oversensitive to a variety of triggers. The early warning signs of a migraine are thought to be due to a narrowing of the blood vessels within the brain, while the pain experienced in the head itself is due to the subsequent expanding or dilating of the blood vessels. The dilation of the blood vessels results in the release of pain-producing substances called prostaglandins. Other chemicals that cause inflammation and swelling, along with some that increase sensitivity to pain are also released. The circulation of these various chemicals, along with the dilation of the scalp vessels stimulates the pain receptors, resulting in a headache.
Migraine headaches can also affect children.
Although many persons who suffer with migraine headaches have a family history of migraine, the exact hereditary mechanism of this disorder is not known. People who get migraines are thought to have an inherited abnormality in the regulation of blood vessels. There is no specific test for diagnosing migraine headaches. The determination that a headache is of the migraine classification comes after a detailed physical examination and history taking between the patient and physician. Patients will be asked a series of questions about their symptoms.