Answer the following question given this paragraph: 

A migraine is a more severe type of headache. It occurs when blood vessels in the head dilate, or expand. This may be triggered by certain foods, bright lights, weather changes, or other factors. People with migraines may also have nausea or other symptoms. Fortunately, migraines can often be relieved with prescription drugs.


Q: When blood vessels in the head dilate, what kind of severe headache can occur?


A:
migraine