Severe headache and nausea are most often caused by a migraine, but go to the ER or call 911 if the headache is sudden and explosive (“worst ever”), comes with very high blood pressure, weakness, confusion, trouble speaking, vision loss, a stiff neck with fever, fainting or follows a head injury. These can signal a stroke, brain bleed, hypertensive emergency or meningitis. Urgent care fits a familiar migraine pattern without red flags.
Medically reviewed by
Board-certified cardiologist · Katy & Sugar Land, TX
Fellowship-trained in cardiovascular disease, interventional cardiology, echocardiography and advanced heart failure and transplant cardiology. Former Assistant Professor of Cardiology at McGovern Medical School.
ER or urgent care for a severe headache with nausea?
The right place depends on the warning signs, not just how bad the pain is. Migraines can be extremely painful yet not dangerous, while a brain bleed can start with a headache that seems manageable.
| Situation | Where to go |
|---|---|
| Sudden, explosive headache that peaks within a minute (“thunderclap”) | Call 911 |
| Headache with weakness, numbness, facial droop, confusion, trouble speaking or vision loss | Call 911 (possible stroke) |
| Headache with blood pressure 180/120 or higher | ER / 911 (possible hypertensive emergency) |
| Headache with fever and stiff neck, or a rash | ER (possible meningitis) |
| Headache after a head injury, or in someone on blood thinners | ER |
| Headache in pregnancy or after delivery with swelling or vision changes | ER (possible preeclampsia) |
| Several people in the home with headache and nausea | Leave the building and call 911 (possible carbon monoxide) |
| Your usual migraine pattern, no red flags, but not controlled at home | Urgent care or your doctor |
| Headache with nausea from a viral illness, dehydration or a hangover, improving | Home care or urgent care |
- Sudden, explosive onset or “the worst headache of my life”
- Weakness, numbness, facial droop, confusion or trouble speaking
- Vision loss, double vision or fainting
- Blood pressure of 180/120 or higher with chest pain or breathlessness
- Fever with stiff neck, or after a head injury
Common causes of severe headache and nausea
- Migraine: throbbing, often one-sided, with nausea, vomiting and sensitivity to light and sound. See MedlinePlus: Migraine.
- Tension or cluster headaches.
- Dehydration, heat illness, hunger and caffeine withdrawal.
- Viral illnesses and sinus infections.
- Medication overuse headache from frequent pain relievers.
When high blood pressure is the cause
Ordinary high blood pressure usually causes no symptoms. But a very high reading, 180/120 or higher, with a severe headache, nausea, confusion, vision changes, chest pain or shortness of breath can be a hypertensive emergency that is damaging the brain, heart, kidneys or eyes. It needs emergency treatment to lower pressure safely. If you have a home monitor, check your blood pressure when a severe headache strikes, and read why blood pressure suddenly rises.
Uncontrolled hypertension is also the leading risk factor for stroke and brain hemorrhage. Long-term control with a blood pressure specialist lowers that risk.
Stroke and brain bleed warning signs
Use BE FAST: Balance loss, Eyes (vision loss), Face drooping, Arm weakness, Speech difficulty, Time to call 911. A sudden, severe “thunderclap” headache can signal bleeding around the brain, even without other symptoms. MedlinePlus stresses that stroke treatment works best when started quickly. Heart rhythm problems such as atrial fibrillation are a major cause of stroke; see post-stroke cardiac care.
What to do while deciding
- Check for red flags in the table and alert box; call 911 if any are present.
- If you have a home monitor, check your blood pressure.
- Rest in a dark, quiet room and sip fluids if you can keep them down.
- Use your usual migraine medicine only if this matches your typical pattern.
- Seek care if the headache does not improve, keeps returning, or changes in character.
When to see a cardiologist
Most headaches are not heart-related, but see a cardiologist if your blood pressure is often high or difficult to control, if you have had a stroke or mini-stroke (TIA) and need heart rhythm or structural evaluation, or if headaches come with palpitations or fainting. Some strokes in younger adults are linked to a patent foramen ovale (PFO).
Blood pressure and stroke prevention care in Katy and Sugar Land
Advanced Cardiology helps patients control high blood pressure and lower stroke risk. Dr. Khalid sees patients at our Katy and Sugar Land offices, with EKG and echocardiogram testing in the office and heart rhythm monitoring available after a stroke or TIA. Learn more about hypertension treatment.
Katy office: 410 W Grand Pkwy S, Suite 4D, Katy, TX 77494
Sugar Land office: 7102 Tarrington Ave, Suite 505, Sugar Land, TX 77479
Phone: (713) 258-6111
We also see patients from Fulshear, Richmond, Rosenberg, Stafford, Missouri City and west Houston.
Headaches with high blood pressure readings?
Get your blood pressure under control. Request a cardiology visit in Katy or Sugar Land.
Having symptoms right now? Call 911. Do not wait for an appointment.
Frequently asked questions
Should I go to the ER or urgent care for a severe headache and nausea?
Go to the ER or call 911 if the headache is sudden and explosive, or comes with weakness, confusion, vision loss, very high blood pressure, fever with stiff neck, fainting or a head injury. Urgent care is reasonable for a familiar migraine pattern without red flags.
Can high blood pressure cause a severe headache and nausea?
Ordinary high blood pressure rarely causes symptoms, but a reading of 180/120 or higher with headache, nausea, confusion or vision changes can be a hypertensive emergency.
What is a thunderclap headache?
A sudden, severe headache that peaks within about a minute. It can signal bleeding in the brain and needs emergency care.
Is a migraine with vomiting an emergency?
Usually not, if it matches your known migraine pattern. It becomes an emergency if it is different from usual, comes with neurological symptoms, or you cannot keep fluids down.
Can a stroke cause headache and nausea?
Yes, especially strokes involving bleeding. Watch for BE FAST signs and call 911.
When should I worry about a headache?
Worry if it is sudden and severe, new after age 50, different from your usual headaches, or comes with neurological symptoms, fever, very high blood pressure or a head injury.
Trusted health resources
- Headache, MedlinePlus, U.S. National Library of Medicine
- Migraine, MedlinePlus, U.S. National Library of Medicine
- Stroke, MedlinePlus, U.S. National Library of Medicine
- High Blood Pressure, National Heart, Lung, and Blood Institute (NIH)
- High Blood Pressure in Pregnancy, MedlinePlus, U.S. National Library of Medicine
Medical disclaimer: This article is for general education and is not a diagnosis or a substitute for care from your own doctor. If you think you may be having a heart attack, stroke or another emergency, call 911 right away.
