When to worry about a headache

Most headaches, even very painful ones, aren't a sign of something dangerous. About 80 to 90 percent of headaches are “primary” headaches, such as migraine and tension-type headache. These aren't caused by a tumor, a blood clot or another serious problem. But a few headaches are a warning sign that needs care right away. This article lists the warning signs doctors look for. It also explains when to call 911, when to go to the emergency room, when urgent care is fine, and when a regular appointment is enough. The goal isn't to worry about every headache. It's to know the few signs that mean “don't wait.”

Call 911 for these headaches

Doctors use checklists of warning signs, such as one called SNNOOP10, to spot the rare headache with a serious cause. Call 911 right away if a headache comes with any of these. Don't drive yourself. Paramedics can start care on the way to the hospital.

• A sudden, severe headache that reaches full strength within a minute, sometimes called a “thunderclap” headache, or the worst headache of your life. This is true even if you often get headaches.
• Signs of a stroke, such as weakness or numbness on one side, a drooping face, trouble speaking or understanding, sudden trouble seeing, or sudden loss of balance.
• Confusion, fainting or a seizure, or being very hard to wake up.
• A headache after a blow to the head that keeps getting worse, or that comes with repeated vomiting, unusual sleepiness, confusion, slurred speech, or one pupil larger than the other.
• Possible carbon monoxide poisoning: a headache with dizziness, nausea or confusion when fumes could be building up, for example from a furnace, a generator or a car running in a garage. Get everyone outside into fresh air, then call 911.

These signs can point to bleeding in the brain, a stroke, a serious head injury or poisoning. All of these need treatment fast.

Know the stroke signs: BE FAST

The CDC and the American Stroke Association teach a quick check called BE FAST:

• B (Balance): sudden loss of balance, dizziness or trouble walking
• E (Eyes): sudden trouble seeing in one or both eyes
• F (Face): ask the person to smile. Does one side of the face droop?
• A (Arms): ask the person to raise both arms. Does one arm drift down?
• S (Speech): ask the person to repeat a simple phrase. Is it slurred or strange?
• T (Time): call 911 right away, even if the signs go away. Note the time they started.

Go to the emergency room now for these

These also need emergency care. Go to the nearest emergency room now. Have someone else drive, or call 911 if you feel very sick or things are getting worse.

• A headache with a fever and a stiff neck. This can be a sign of meningitis, which needs treatment fast.
• A headache during pregnancy or in the year after giving birth that won't go away or keeps getting worse, or that comes with blurry vision, flashing lights, blind spots or dizziness. Tell the staff you are pregnant or were pregnant in the past year.
• A severe headache with sudden, intense pain in one eye, a red eye and blurry vision. Some people also have nausea.
• Age 50 or older with a new headache plus vision changes or jaw pain when chewing. Inflamed blood vessels (giant cell arteritis) can cause these and can lead to sudden, permanent vision loss.
• A child with a headache and a rash, fever or unusual sleepiness, or with a headache after a head injury.

Call your doctor today for these

These signs don't usually need an ambulance, but they do need a doctor to check you soon. Call your primary care doctor's office today and describe what's going on. If you can't reach anyone and the headache is severe or getting worse, go to the emergency room.

• A new kind of headache, or a big change in your usual headaches: more often, more severe or different
• A headache that keeps getting worse over days or weeks, or one that never goes away
• New headaches that start at age 50 or older
• A headache that gets much better or worse when you stand up or lie down
• A headache brought on by coughing, sneezing, straining, exercise or sex
• A new headache if you have had cancer, or if your immune system is weak because of HIV or medicines such as chemotherapy or steroids
• A headache with a fever that won't go away, weight loss or night sweats
• A headache after a blow to the head, even if the blow seemed minor. Older adults should be checked right away, especially if they take a blood thinner.

Where urgent care fits

Urgent care is for problems that aren't life-threatening but can't wait for your own doctor. For headaches, that might be a migraine attack like your usual ones that isn't easing with your usual plan, when your doctor's office is closed. Urgent care isn't the place for any of the warning signs above. For those, go to the emergency room or call 911.

If you're not sure where to go, call your doctor's office. After hours, your call may go to a nurse or doctor on call. Your health plan may also have a nurse advice line.

When a regular appointment is fine

If your headaches follow your usual pattern and you have none of the warning signs, a regular appointment is the right step. Book one with your primary care doctor if:

• Headaches happen several times a month or get in the way of work, school or family life.
• You take headache medicine, over-the-counter or prescription, on 10 or more days a month. The medicine itself can start causing headaches. See Medication overuse headache.
• Your usual medicine doesn't help as much as it used to.

A primary care doctor is a good place to start and can refer you to a neurologist if needed. For tips on finding a headache specialist, see How to find a headache specialist, or try the American Migraine Foundation's doctor finder.

If you already have migraine

Having migraine doesn't make a dangerous headache more likely. But because you're used to headaches, a warning sign can be easier to miss. What matters most is change: a headache that is sudden, different or doesn't fit your usual pattern.

Sudden, big changes need care right away. Slower changes, such as attacks slowly becoming more frequent, are a reason to book an appointment. Before you go, write down how the new headaches differ from your usual ones.

If you have migraine with aura, call 911 for weakness on one side of the body. Also call 911 for aura that is new for you, starts suddenly or feels different from usual. See a doctor soon if your aura lasts more than an hour or doesn't go away. Learn more in What is migraine?

Keep a record so changes stand out

Changes are easier to spot when you have a record. Note each headache day, how long it lasted, how bad it was, and what medicine you took. Then you can answer questions like “Is this one different?” and “Are they getting more frequent?” See How to keep a headache diary.

With Zutsu Note, you can log headaches and medicines in a few taps and see your headache days each month on a chart. You can also show a 30-day summary at your appointment on your phone, or print it or save it as a PDF if you use Zutsu Note in a web browser. But a record can't tell you whether a headache is dangerous. If you have a warning sign, get care first and log it later.

Studies and guidelines we used

• Do TP, et al. Red and orange flags for secondary headaches in clinical practice: SNNOOP10 list. Neurology. 2019;92:134-144.
• Headache Classification Committee of the International Headache Society. The International Classification of Headache Disorders, 3rd edition (ICHD-3). Cephalalgia. 2018;38:1-211.
• American Migraine Foundation. Changes in Headache: When to See Your Doctor.
• National Institute of Neurological Disorders and Stroke. Headache.
• National Library of Medicine, MedlinePlus. Headache; When to use the emergency room (adult).
• Centers for Disease Control and Prevention. Signs and Symptoms of Stroke; Urgent Maternal Warning Signs; Mild Traumatic Brain Injury and Concussion: Information for Adults; Facts About Older Adult Falls; Carbon Monoxide Poisoning Basics; Meningitis.
• National Eye Institute. Types of Glaucoma.
• American College of Rheumatology. Giant Cell Arteritis.