Headache After a Car Accident: Causes and When to Worry

Quick Answer

A headache after a car accident usually comes from one of three places: the neck (a cervicogenic headache caused by whiplash), tight muscles in the head and shoulders, or a concussion. It can start hours or days after the crash, once adrenaline fades and inflammation builds. Most are treatable, but a headache that is severe, sudden, or getting worse needs emergency care first.

Headaches that begin after a crash are common and are not something to wait out.
The neck is the most frequent source. Whiplash irritates joints and muscles that refer pain into the head.
A headache can start days later. Doctors count it as crash-related when it begins within about a week.
Severe, sudden, or worsening headaches, or headaches with vomiting, confusion, or weakness, are an emergency.
Treatment depends on the type, so the first step is an exam that sorts out which one you have.

You walked away from the crash feeling shaken but fine. Now it is two days later and you have a headache that will not let go. A headache after a car accident is one of the most common delayed symptoms we see, and where it comes from decides how it should be treated.

Why does my head hurt after a car accident?

In a collision your head keeps moving after your body stops. Even without hitting anything, that motion strains the joints, ligaments, and muscles of the neck, and it can jolt the brain inside the skull. Either one can cause a headache. So can the hours of clenched, guarded muscles that follow.

What kind of headache do I have?

Cervicogenic headache: pain that starts in the neck and spreads to the back of the head, the temple, or behind one eye. It often gets worse when you turn your head or hold one position. This is the classic whiplash headache.
Tension-type headache: a dull band of pressure across the forehead or around the head, from tight neck, shoulder, and scalp muscles.
Post-concussion headache: a headache that comes with fogginess, light or noise sensitivity, dizziness, nausea, or trouble concentrating. You do not have to hit your head or black out to have a concussion.
Occipital nerve irritation: sharp, shooting, or electric pain that runs from the base of the skull up the back of the head.

These overlap, and it is common to have more than one. That is why guessing from a list is less useful than an exam. If you had headaches before the crash and are not sure which kind they were, Total Health Systems, a multi-specialty clinic in Michigan, has a clear guide to telling tension headaches and migraines apart.

Is it normal for a headache to start days after a crash?

Yes. Adrenaline masks pain at first, and inflammation in the neck takes time to build. Many people feel the first headache the next morning or two to three days later. Headache specialists classify a headache as post-traumatic when it begins within seven days of the injury, so a delay does not mean it is unrelated to the crash.

7 days

window for a post-traumatic headache to begin

A headache that starts within a week of an injury is classified as related to that injury.

When is a headache after a car accident an emergency?

Go to the ER or call 911 if you have

A sudden, severe headache or the worst headache of your life. A headache that keeps getting worse. Repeated vomiting. Confusion, unusual drowsiness, or trouble waking. Slurred speech, weakness, numbness, or loss of balance. A seizure. One pupil larger than the other. Clear fluid from the nose or ears. Any headache after a crash if you take blood thinners.

The ER said I was fine. Why do I still have headaches?

The ER checks for bleeding, fractures, and other emergencies, and a clear scan is good news. But neck joint and muscle injuries do not show on a CT scan or a standard X-ray, and they are the most common reason headaches continue. We explain what ER imaging does and does not show in X-rays and MRIs after a car accident, and when each kind of care fits in chiropractor vs ER after a car accident.

How is a headache after a car accident treated?

It depends on the type. We start with an exam of your neck, a neurological screen, and questions about how the headache behaves. If anything points to a concussion or another problem outside our scope, we refer you to the right provider. For headaches that come from the neck and surrounding muscles, care may include:

Gentle joint mobilization or chiropractic adjustments, when the exam shows they are appropriate
Soft-tissue work and massage for guarded neck and shoulder muscles
Specific exercises to restore neck movement and strength
Acupuncture for selected pain patterns
Guidance on sleep position, screen time, and activity while you heal

What can I do until I am seen?

Write down when the headaches start, where the pain sits, and what makes it better or worse.
Keep your neck moving gently within comfort. Do not force stretches.
Cut back on screens and bright light if they make it worse.
Follow the label on any over-the-counter medication, and ask a pharmacist or doctor if you are unsure what is safe for you.
Do not drive if you are dizzy or foggy.

Does insurance cover headache treatment after a crash?

If the headaches began after the accident, treatment is generally handled like the rest of your accident care. In Colorado that often means Med-Pay on your own auto policy, which pays regardless of fault. See Colorado Med-Pay explained. Getting examined early also creates a record that ties the headaches to the crash. This is general information, not legal advice.

Headaches since your accident?

Let us find out where they are coming from. Your consultation is free. Call (303) 577-2040 or book online in Aurora, Denver, or Wheat Ridge. We accept all auto insurance and handle the paperwork. Hablamos español. Chúng tôi nói tiếng Việt.

Headache After a Car Accident: Why It Starts Days Later and When to Worry