One: A very sudden headache that gets progressively worse, and may include nausea, vomiting or dizziness (may be caused by a stroke).
Two: A spontaneous headache that is worse than any other headache (may be caused by an aneurysm).
Three: Terrible headaches that start after age 50.
Four: Headaches that are followed by impaired memory or balance, dizziness, numbness or tingling in extremities (may be caused by a stroke).
Five: Headaches that get worse with coughing or sneezing (may be an infection in the brain).
Six: Headache that sets in following an injury to the head (may be caused by a hemorrhage).
Seven: Headaches that are present simultaneously with a fever (may be caused by spinal meningitis).
Eight: A pulsating pain around the eye that may spread to the ear or neck and is not alleviated by pain medication (may indicate a blood clot).
If you are unsure as to whether or not your headaches are indicative of a dangerous medical issue or just an ordinary migraine, you should see a neurologist to be safe.