Because you have migraines, getting a bad headache is not new to you. If your migraine pattern changes or your headaches suddenly feel different, it could be a sign of a more serious health condition.

Contact your doctor right away if you have any of the following:

• A severe headache that comes out of the blue. This is sometimes described as a "thunderclap." Migraine headaches can be severe at times, but contact your doctor if you have a headache that comes on suddenly in a different way than your usual migraines and feels like the "worst of your life."
• A headache with fever, neck stiffness, skin rash, confusion, double vision, weakness, numbness, or trouble speaking
• A headache linked to seizures
• A headache after a recent sore throat or respiratory illness. During cold and flu season, when sore throats are common, you may have migraines more often. The warning sign of something more serious is usually when the sore throat goes away, but then fever, stiff neck, or really severe headaches develop.
• A headache that follows a head injury, especially if it keeps getting worse
• A chronic headache that is triggered when you exert yourself or gets worse if you cough or move suddenly
• Unfamiliar headache pain after age 50
• Headache pain that you need to take medicines for daily, but that your doctor did not prescribe as preventive (prophylactic) medicine

Go to the ER if you have any of the above symptoms and a serious health condition. This includes liver, heart, or kidney disease or a disorder that affects your immune system, such as HIV. Also go to the ER if you have these symptoms and you are pregnant. And if your new symptoms include weakness, vision loss or double vision, or confusion.