Migraines are a type of vascular headache. They involve blood vessels, as well as nerves and chemicals in the brain. They are most likely caused by an abnormal trigger of chemicals that cause the blood vessels to swell. Migraines differ from other types of headaches because they often are more severe and are accompanied by other symptoms. In patients with aura, they can have unusual symptoms such as nausea or fatigue even two days before the onset of full-blown migraine.

Often described as a throbbing headache, migraines are usually felt on only one side of the head. They typically begin as a dull ache near the side of the forehead. Over a period of several minutes to hours, the ache intensifies to a disabling pain. The pain is often so severe that people may be sensitive to anything touching their head (allodynia).

Without treatment, the headache may last anywhere from four to more than 72 hours. During this time, a person may experience a number of additional symptoms including nausea, vomiting and sensitivity to light. The pain associated with a migraine is referred pain, meaning it is usually felt around the eye or temple area, but it may develop in the face, sinus, jaw or neck.

According to National Headache Foundation (NHF), more than 28 million Americans experience migraines. The frequencies in which migraines are experienced vary from person to person. Some people experience migraines once or twice a year, whereas others will experience them several times a month.

Migraine symptoms appear differently among individuals. None of the symptoms develop in all individuals, making the diagnosis of the condition more difficult.  In a large study conducted by the NHF in 1999, 48 percent of the individuals with migraines reported that they had received a medical diagnosis. Even today, the NHF estimates that less than half of the people who suffer with migraines receive a medical diagnosis.

Although migraines pose little risk of long-term damage to a person’s overall health, the debilitating pain can interfere with daily life. In addition, there is a very low risk of stroke associated with severe migraines. This may result from a narrowing of the blood vessels, which reduces blood flow to parts of the brain. Permanent neurological changes, such as muscle weakness, may also occur as the result of complicated migraines.

Severe headaches from a number of serious conditions may be mistaken for migraines. These headaches may be caused by:

• Stroke or intracerebral hemorrhage (bleeding in the brain resulting from the rupture of a blood vessel within the head)
  
  
• Blood clot or aneurysm (an abnormal expansion or ballooning of a section of an artery)
  
  
• Brain tumor
  
  
• Concussion
  
  
• Temporal arteritis (inflammation of arteries in the head)
  
  
• Cranial neuralgias (pain in nerves of the head)
  
  
• Encephalitis or meningitis
  
  
• Lyme disease

As a result, patients should discuss all serious or recurring headaches with their physician and seek medical attention when a headache:

• Starts suddenly
• Is severe or persistent
• Disturbs sleep
• Occurs during activity
• Changes in pattern or intensity
• Intensifies after lying down
• Is accompanied by other symptoms, such as drowsiness or vision changes

Emergency medical treatment should be sought when:

• A headache is accompanied by unusual symptoms not experienced with previous migraines, including:
  
  
• Speech problems
• Vision abnormalities
• Numbness, weakness or loss of balance
• Difficulty moving a limb
• Fever
• Stiff neck
• Rash
• Seizures or mental confusion
  
  
• A headache occurs soon after a sore throat or respiratory infection
  
  
• A headache occurs after a head injury
  
  
• A chronic headache intensifies with coughing, exertion, straining or sudden movement
  
  
• A new type of headache pain occurs (in those over age 50 or younger than 8)
  
  
• A new type of headache pain occurs that is severe and not contained to just one side of the head
  
  
• There is loss of consciousness