The headaches may recur from time to time throughout life. The condition tends to run in families. It affects women three times more often than men. For years migraine headaches were thought to be caused when blood vessels in the head contract and then swell, producing pain. Before a migraine starts, there is often a warning period when you don't feel well.
Some people lose part of their vision or see bright spots or zigzag patterns in front of their eyes.
These symptoms, which may precede and predict a migraine headache, are called migraine aura. The vision changes of the aura usually go away as the headache begins. The pain is usually more severe on one side of the head but can affect the whole head. Your health care provider will ask about your symptoms and medical history and give you a physical exam. A careful history of your headaches is very helpful.