Almost everyone gets headaches. Most of them are the ordinary kind, the sort that fades after a glass of water, a meal, or a few hours away from a screen. A small number are something else entirely, and they arrive wearing the same disguise.
That’s the genuine difficulty. You’re trying to make a careful decision at the exact moment your head hurts too much to think clearly, and the advice you find online tends to swing between “it’s probably nothing” and “it could be a brain bleed.” Neither helps at two in the morning.
This guide lays out the specific signs that separate a bad headache from a medical emergency, what those signs usually mean, and what actually happens during a headache evaluation. Arlington ER is open 24 hours a day at 1607 S. Bowen Rd. in Pantego, with board-certified emergency physicians and on-site CT imaging, so the answer never has to wait until morning.
Most Headaches Are Not Emergencies
The majority of headaches come from causes that resolve on their own: dehydration, skipped meals, poor sleep, eye strain, tight neck and shoulder muscles, or stress that finally catches up with you on a Friday evening.
These usually build gradually, feel like pressure or a dull band around the head, and ease with rest, fluids, and quiet. They don’t come with neurological symptoms, they don’t wake you from a deep sleep, and they follow a pattern you recognize from previous headaches.
Recognizing the ordinary kind matters, because it makes the unusual kind stand out. When a headache breaks your normal pattern, that break is the signal.
The Warning Signs That Mean Go Now
Go to an emergency room right away, or call 911, if a headache comes with any of the signs below. Each one points toward a cause that needs imaging and evaluation the same hour, not the same week.
- Sudden, severe pain that reaches full intensity within seconds or a minute
- The worst headache you have ever had, especially if it feels different in kind, not just degree
- Weakness, numbness, or drooping on one side of the face or body
- Slurred speech, or trouble finding or understanding words
- Sudden vision loss, double vision, or a visual change that does not fade
- Fever with a stiff neck, particularly if bending the chin toward the chest hurts
- Confusion, unusual drowsiness, or difficulty staying awake
- A seizure, or fainting
- Head pain that follows a fall, a collision, or any blow to the head
- Vomiting that will not stop, or that prevents you keeping fluids down
None of these are subtle once you know to look for them. If one applies, the decision has already been made for you.
What a Thunderclap Headache Means
A thunderclap headache reaches maximum intensity almost instantly, usually within a minute of starting. People describe it as being struck, or as a switch flipping. The distinguishing feature is not how badly it hurts, but how fast it got there.
That speed matters because it can indicate bleeding around the brain. Blood that escapes a vessel irritates surrounding tissue immediately, which is why the pain arrives without any build-up. A migraine, even a severe one, almost always climbs over minutes to hours.
A thunderclap headache is an emergency every time, including when the pain eases afterward. Improvement does not mean the cause resolved.
Headache or Stroke? How to Tell
Stroke symptoms and migraine with aura can look alike from the outside, which is exactly why so many people hesitate. The pattern of onset usually separates them.
| Sign | Migraine With Aura | Stroke |
| How it starts | Builds gradually over 5 to 20 minutes | Sudden, full intensity within seconds |
| Vision changes | Flashing lights, zigzag patterns, blind spots that drift | Sudden loss of vision, often in one eye or one field |
| Sensation | Tingling that spreads slowly from one area to another | Sudden numbness or weakness, usually one whole side |
| Speech | Usually unaffected | Slurred, garbled, or hard to produce |
| Face | Normal | Drooping on one side |
| What to do | Rest and evaluate; come in if severe or unfamiliar | Call 911 immediately |
If you are weighing the two and cannot decide, treat it as a stroke and call 911. Stroke care is measured in minutes, and paramedics can begin assessment before you arrive anywhere.
Headaches After a Head Injury
Any headache that follows a fall, a car accident, a sports collision, or a knock to the head deserves evaluation, even when the impact seemed minor and even when you never lost consciousness.
Bleeding inside the skull does not always announce itself right away. Symptoms can surface hours or occasionally days later, as pressure gradually builds. Older adults carry higher risk, because bleeding tends to start more easily and stop less readily with age.
Warning signs after a head injury include a headache that steadily worsens rather than settles, repeated vomiting, increasing confusion or drowsiness, unequal pupil size, or difficulty waking someone who has gone to sleep. Any of those means going in immediately.
Headache With Fever and a Stiff Neck
The combination of headache, fever, and a neck too stiff to bend forward is a recognized emergency pattern. It can signal inflammation of the membranes surrounding the brain and spinal cord, which progresses quickly and needs same-hour treatment.
Other symptoms often appear alongside: sensitivity to light that feels far beyond normal, nausea, confusion, and sometimes a rash that does not fade when a glass is pressed against it. In infants, the signs can be quieter, showing up as unusual irritability, poor feeding, or a bulging soft spot on the head.
This is not a wait-and-see situation. If those three signs appear together, go in.
When a Migraine Crosses Into Emergency Territory
Living with migraine means learning to ride out attacks at home, which is reasonable most of the time. There are three situations where that changes.
The first is duration. A migraine that runs past 72 hours without breaking is no longer following its usual course, and prolonged attacks carry a real risk of dehydration.
The second is fluid loss. If vomiting has stopped you keeping water down, dehydration compounds the headache and each makes the other worse.
The third, and the most important, is novelty. A migraine that brings symptoms you have never had before, or that feels categorically unlike your usual attacks, deserves evaluation rather than endurance. Familiarity with your own migraines is useful right up until the moment something changes.
For more on how we treat migraine specifically, see our Migraine & Severe Headache Treatment page.
Headaches Worth Checking Even When They Are Not Emergencies
Some headaches do not need an ambulance but should not be ignored either. Book an evaluation if you notice any of these patterns:
- A new headache pattern that begins after age 50
- Pain that worsens when you lie down, cough, sneeze, or bend over
- Headaches that wake you from sleep consistently
- A headache that has been slowly worsening over weeks rather than fluctuating
- Headaches that appear alongside a change in vision, balance, or memory
- A change in the character, location, or frequency of headaches you have had for years
These patterns are worth investigating because they suggest something is driving the pain rather than simply triggering it.
What Happens During a Headache Evaluation at Arlington ER
Head pain moves to the front of the queue, whether you arrive by ambulance or walk through the door.
- Immediate triage. Vitals, a brief history of how the pain started, and how quickly it escalated. Onset speed is one of the most useful pieces of information you can give us.
- Neurological examination. Vision, pupil response, facial symmetry, strength, coordination, reflexes, and speech, performed at the bedside within minutes.
- CT imaging. Our on-site scanner rules out bleeding, swelling, and pressure inside the skull. Results are read here, not sent out and returned days later.
- Laboratory testing. Blood work checks for infection, dehydration, and electrolyte imbalance, each of which can drive or worsen head pain.
- Treatment and reassessment. Care begins while results come back, and you are reassessed as the picture develops.
- A plan you leave with. Written instructions covering what was found, what was ruled out, and the specific symptoms that should bring you back.
Because imaging and labs run in the same building, most patients have real answers within the hour rather than a referral and a waiting period.
What You Can Do Before You Arrive
If you are heading in, a few things help.
Note the time the headache started and how long it took to reach its worst. Write it down if you can, because that detail is easy to lose once pain and adrenaline take over, and it genuinely shapes the evaluation.
Rest somewhere dark and quiet, keep sipping water if you are able to keep it down, and avoid screens. A cool cloth across the forehead or the back of the neck helps some people.
Do not drive yourself if you have any weakness, vision changes, confusion, or pain severe enough to distract you. Have someone else drive, or call 911. Bring a list of anything you take regularly and note any recent illness, injury, or change in routine.
Frequently Asked Questions
Should I go to the ER or urgent care for a severe headache?
Choose the emergency room. Urgent care clinics do not have CT imaging, so they cannot rule out bleeding or pressure inside the skull, which is the main reason a severe headache needs evaluation.
How fast does a thunderclap headache come on?
It reaches maximum intensity within about a minute, often within seconds. That speed is the defining feature and separates it from a migraine, which typically builds over a longer period.
Can dehydration alone cause a severe headache?
Yes. Dehydration is a common cause of significant head pain, particularly during Texas summers. It usually improves with fluids, so pain that persists despite rehydrating deserves a closer look.
Is a headache with a fever always serious?
Not always, since many ordinary infections cause both. The combination becomes urgent when a stiff neck, confusion, light sensitivity, or a rash appears alongside them.
How long is too long for a headache to last?
A headache running past 72 hours without breaking should be evaluated, even one that follows your usual migraine pattern. Prolonged attacks raise the risk of dehydration and become harder to resolve.
Do I need a referral to be seen for a headache at Arlington ER?
No. Arlington ER is walk-in and open 24 hours a day, every day of the year. No appointment or referral is needed at any hour.
Will a CT scan be part of my headache evaluation?
Often, though not always. Your physician decides based on how the pain started, your examination findings, and your history. When imaging is needed, it happens on-site during the same visit.
My headache eased on the way here. Should I still be seen?
Yes, particularly if it started suddenly or severely. Some serious causes ease temporarily before returning, so improvement on its own does not rule anything out.
If You Are Unsure, Come In
Deciding whether head pain is dangerous by how much it hurts is unreliable in both directions. Serious causes sometimes feel manageable, and ordinary ones sometimes feel unbearable. An examination and a scan settle the question in far less time than most people spend deliberating.
Arlington ER is open right now, and every hour of every day, with board-certified emergency physicians and on-site imaging ready the moment you arrive.
Call Now: 817-973-7406
Hours: 24/7/365
Walk-In: Arlington ER, 1607 S. Bowen Rd., Pantego, TX 76013
No appointment or referral needed. Most major insurance accepted.
