A headache after a car accident can start at the scene or arrive late: often one to three days later, and up to 10 days after even a minor crash, like other crash injuries. Many begin at the base of the skull. If you hit your head, feel confused or get a sudden, severe headache, go to the ER first.
How does a crash headache unfold, from the scene to months later?
- At the scene. Adrenaline and stress hormones can block pain signals, so many people feel fine. Cleveland Clinic notes that some whiplash symptoms begin right after a crash, while others take at least 12 hours to appear.
- One to three days. As the adrenaline wears off, pain and stiffness surface, and some people wake up unable to turn their head. Get examined within 72 hours, even if you still feel fine.
- Up to day 10. Even after a minor accident, headaches, dizziness and blurred vision can start late, and so can shoulder or arm pain and a stiff lower back. Write down the day and time each symptom begins, even slight stiffness.
- Four to eight weeks. Muscles tighten around an injury to protect it, which is normal. If motion isn’t restored within 4–8 weeks, scar tissue can form and make a full recovery harder.
- Months later. An accident months ago can still show up as stiffness or headaches, and it isn’t too late to get checked.
Why whiplash symptoms run late, and how long the neck pain itself tends to last, is covered in how long whiplash lasts.
Why does a neck injury cause a headache?
Whiplash is a sudden, poorly restrained acceleration and deceleration of the head that bends the neck forward and back, and it can follow low- as well as high-impact forces, according to the International Classification of Headache Disorders (ICHD-3). The same classification links a headache to whiplash when the injury came with neck pain or headache at the time and the headache developed within 7 days. Cleveland Clinic lists headaches among whiplash symptoms. ICHD-3 adds that the headache can come on its own or with other neck symptoms, and sometimes with changes in sensation, concentration or mood.
A headache that starts at the base of your skull, sometimes with dizziness or blurred vision, is one of the signs to come in after a crash. Headaches that start in the neck more generally are covered on our headaches and migraines page, and the neck injury itself on whiplash.
When is a headache after a crash an emergency?
Go to the ER first if you hit your head, feel confused or have a sudden, severe headache, or if you notice new weakness in an arm or leg or changes in bladder or bowel control. After any bump, blow or jolt to the head, the CDC says to call 911 or go to the nearest emergency department for a headache that gets worse and does not go away, repeated nausea or vomiting, slurred speech, weakness or numbness, seizures, increasing confusion or drowsiness, or one pupil larger than the other.
The ER is built to rule out emergencies like these. Its X-rays show broken bones, not strained ligaments and muscles, so once you’ve been cleared, keep your discharge papers for your exam.
What does an exam for a post-crash headache look like?
Dr. Gurj Kalay, DC, starts by asking how the collision happened, from a rear or side impact to where your headrest sat, and when each symptom began. The mechanics shape the injury. He then checks your alignment, range of motion, strength and reflexes, looking for the soft-tissue injury an X-ray isn’t designed to show.
Bring your ER or urgent care discharge papers, which show what was already ruled out, and your notes on when the headache started, where it sits and what makes it worse. The exam comes before any treatment, and Dr. Kalay walks you through what he found first.
Can a headache show up days after a car accident?
Yes. Pain can take up to 10 days to appear after even a minor accident, and headaches are among the symptoms that start late. A note of the day it began, and what you were doing, helps the exam connect it to the crash.
Is a headache after a minor fender bender normal?
A minor crash doesn’t rule one out. ICHD-3 notes that whiplash can follow low-impact forces, and impacts under 10 mph can be enough to cause it, since the force still travels through you when the bumper shows little. A dull headache with a stiff neck is worth an exam within days; one that is severe or getting worse needs the ER.
Could a headache after a crash be a concussion?
It could, if your head was struck or jolted. The CDC lists a headache that gets worse and does not go away among the concussion danger signs that call for 911 or the emergency department. Concussion is a diagnosis for a medical doctor, and a chiropractic exam does not rule it out.
What kind of headache does whiplash cause?
Doctors classify it as a headache attributed to whiplash. Under ICHD-3, it is acute while it lasts less than 3 months, and persistent once it has gone on for more than 3 months after it began.
If a headache has started since your crash and none of the emergency signs apply, book an exam and bring your notes on when each symptom began. Our blog has more on injuries and recovery.
Sources
- “5.3 Acute headache attributed to whiplash.” The International Classification of Headache Disorders, 3rd edition (ICHD-3). International Headache Society. ichd-3.org
- “5.4 Persistent headache attributed to whiplash.” The International Classification of Headache Disorders, 3rd edition (ICHD-3). International Headache Society. ichd-3.org
- “Signs and Symptoms of Concussion.” HEADS UP, Centers for Disease Control and Prevention. cdc.gov
- “Whiplash (Neck Strain).” Cleveland Clinic. my.clevelandclinic.org
