Concussion: The Red Flags
In 10 minutes you'll know the danger signs that mean a concussion needs the ER right now, and when it's safe to just watch and wait.
Print this course — or save it as a PDF from the print dialog. Good for a fridge, a glovebox, or a waiting room.
Why this matters
A concussion is a brain injury from a hit or jolt that shakes the brain inside the skull. You do not need to black out for it to count — most people with a concussion never lose consciousness. Most people recover within a couple of weeks (Centers for Disease Control and Prevention), but a small set of danger signs mean the brain needs care right now.
Know the signs
The HEADS UP danger signs
Most concussions do not need an emergency room. The CDC's HEADS UP program lists danger signs that always do, because they can mean bleeding or swelling inside the skull.
- One pupil (the black center of the eye) looks larger than the other
- A headache that keeps getting worse, not better
- Vomiting more than once
- Slurred speech
- Can't be woken up, or is getting drowsier, not more alert
- A seizure
- New weakness or numbness in an arm or leg
- Unusual behavior or confusion that keeps getting worse
- In a baby: crying that will not stop
Any one of these means call 911 or get to an emergency room now.
You don't have to black out for it to count
Most concussions happen without anyone blacking out. The person might just seem dazed, say they "see stars," or feel foggy. None of that means an emergency room visit.
The mistake is deciding "they didn't pass out, so they're fine." A hard hit to the head, or a whiplash-style jolt, can cause a real concussion with no loss of consciousness. What matters is whether any danger sign shows up, not whether they blacked out.
When in doubt, sit them out
After a hit to the head during a game or practice, the safest rule is simple: when in doubt, sit them out. Do not send them back in to "finish the game," even if they insist they feel fine.
Anyone with a suspected concussion needs a same-day medical evaluation before returning to any sport, and many states require written clearance from a health care provider.
This rule exists because of second-impact danger: a second hit before the first concussion heals can be far more dangerous than the first one alone.
Watching closely for the first day or two
For the first day or two after a head injury, keep a closer eye on the person than usual. You do not need to wake them every couple of hours through the night — current guidance does not call for that routinely. Let them sleep, and follow your doctor's advice.
Watch for change: mild symptoms turning severe, or a new danger sign appearing that wasn't there before. If any sign from the list above shows up, call 911 or go to the emergency room, even if the injury first seemed minor.
In babies and young children
Babies and toddlers cannot tell you they have a headache or feel foggy, so you are watching behavior instead. A baby who cries and cannot be consoled is one of the danger signs by itself.
Also watch for vomiting after any fall or bump to the head, even if the child seemed fine right after. One episode can happen with an ordinary bump, but vomiting more than once is a reason to call 911 or go to the emergency room.
How it really looks
I'm fine, coach, put me back in
Jonas goes up for a header and knocks skulls with another player. He gets up laughing it off, jogs to the sideline, and tells his coach, "I'm fine, put me back in." His coach has done this course and knows a blackout isn't the test. She notices he seems a little dazed and slow to answer a simple question, and he mentions the field looks fuzzy for a second. None of that is a danger sign, but she sits him out for the rest of the game and calls his mom. Jonas sees his pediatrician that afternoon and is cleared to return to practice six days later, frustrated about missing the tournament but otherwise fine.
Fine after the fall, until the second time he throws up
Adaeze's eighteen-month-old son tumbles off the couch and bumps his head on the coffee table. He cries hard for a minute, then seems back to normal, so she watches him instead of rushing anywhere. An hour later he throws up. Twenty minutes after that, he throws up again and seems unusually sleepy for the middle of the afternoon. Adaeze remembers that repeated vomiting after a head bump is one of the signs that means go now, so she calls 911 rather than waiting to see if a third episode happens. At the emergency room, doctors check him over and send them home the same evening, reassured rather than second-guessed for calling.
What to do until help arrives
- Check for the danger signs above right after the injury, and keep checking for a day or two.
- Call 911 or go to the emergency room right away if any danger sign is present, even just one.
- Keep them out of any game or rough play for the rest of the day, no matter how fine they feel.
- Apply a cold pack wrapped in cloth to any swelling, and let them rest quietly.
- Write down how the injury happened and what symptoms showed up, and when.
- Arrange a same-day medical evaluation before any return to sports or rough play.
- Let them sleep as needed; you don't have to wake them every few hours unless a clinician says to.
Myths & mistakes
People often think a concussion always means someone was knocked out.Actually most concussions happen without any loss of consciousness. Watching for the danger signs matters more than watching for a blackout.
People often think you have to wake someone up every couple of hours all night after a head injury.Actually current guidance does not call for that routinely. Let them sleep, and follow your doctor's instructions if you have them.
People often think if the person feels fine and wants to keep playing, it's safe to let them.Actually when in doubt, sit them out. A second hit before the brain heals can be far more dangerous than the first, so a same-day medical check comes before any return to play.
What you learned
- You can spot the HEADS UP danger signs that always mean go to the emergency room.
- You know a concussion does not require losing consciousness to be real and serious.
- You know the rule for sports: when in doubt, sit them out, and get a same-day check before returning.
- You know you don't have to wake someone every couple of hours overnight unless a clinician tells you to.
- You know new or worsening symptoms in the first day or two still deserve an emergency call.
Sources
- Centers for Disease Control and Prevention — HEADS UP: concussion signs, symptoms, and danger signs
- American Academy of Pediatrics — Concussion recognition and return-to-play guidance for children
Spot an error? Tell us — accuracy matters more to us than being fast.
Common questions
My child didn't lose consciousness. Can it still be a concussion?
Yes. Most concussions happen without anyone blacking out, and loss of consciousness is not required for a diagnosis. What matters more is whether any danger signs are present, such as a headache that keeps getting worse, repeated vomiting, unusual drowsiness, or confusion that is getting worse instead of better. Without those, most concussions can be watched at home and checked by a doctor when convenient.
Do I need to wake them up every couple of hours during the night?
Not routinely. That advice is outdated for most situations, and current guidance does not call for repeated overnight wake-ups. Sleep helps the brain heal. What matters is watching for danger signs in the first day or two and calling 911 or going to the emergency room if any appear, day or night. If a clinician gave you specific instructions for your situation, follow those instead.
When can they go back to sports after a concussion?
Not until a health care provider has evaluated and cleared them, even if they feel completely fine. Many states legally require written clearance before a young athlete returns to play. This rule exists because a second head injury before the first one heals can be far more dangerous than the first, so a same-day evaluation and a proper waiting period protect against that risk.
Check what you know
Five questions. Four correct to pass. Retake as many times as you like — this is practice, not a test.
Keep going
This course belongs to Protecting Young Kids. Courses that pair well with it:
From other readers
Comments are read by a person before they appear. Please do not post medical advice or anything about a specific person's health — this is not the place for it, and it will not be published.
If this is an emergency, do not comment. Call 911.