Call an ambulance now if the headache is:
Saudi Arabia: 997 ambulance, or 911 unified emergency number. UK 999 · US 911 · most of Europe 112.
- Sudden and severe, reaching its worst within about a minute, like being hit on the head. This is called a thunderclap headache.
- With weakness or numbness on one side, a drooping face, trouble speaking, loss of vision or double vision, or loss of balance.
- With fever and a stiff neck, a rash that doesn’t fade when pressed, or new confusion.
- With a seizure, fainting, or unusual drowsiness.
- After a blow to the head, especially in someone taking blood thinners or who is elderly.
- New and severe during pregnancy or in the weeks after giving birth, especially with swelling, vision changes or high blood pressure.
- With a red, painful eye and blurred vision.
Don’t wait to see whether it settles, and don’t drive yourself.
See a doctor soon, within days, if:
The headache is new after 50, keeps getting worse over weeks, wakes you, or worsens with coughing or straining.
- A new headache starts after the age of 50.
- The headache is new, and gets steadily worse over days or weeks.
- It wakes you from sleep, or is worst on waking with vomiting.
- It is set off by coughing, sneezing, straining or exercise.
- It changes when you lie down or stand up.
- Your usual headache pattern has changed clearly.
- You have cancer, HIV or another condition that weakens immunity.
- Over 50 with pain at the temples, pain on chewing, or sudden vision changes. This needs to be seen the same day.
- You take painkillers on 10 or more days a month.
Your usual headache
A headache that is like your previous ones, with none of the signs above, is usually your known headache, even when it is bad.
Migraine can be severe and come with vomiting, sensitivity to light, and even an aura with zigzag lines or tingling. If this has been diagnosed and the attack is like your usual ones, it is not a warning sign by itself. What matters is change: a new kind of headache, a new symptom, or a different aura.
Medical sources
Do TP et al. · Neurology · 2019Red and orange flags for secondary headaches in clinical practice: SNNOOP10 list. Neurology 92(3):134–144. doi.org/10.1212/WNL.0000000000006697
The warning signs that point to a secondary headache.
NICE · Guideline CG150Headaches in over 12s: diagnosis and management. nice.org.uk/guidance/cg150
Which headaches need further assessment.
International Headache Society · Cephalalgia · 2018The International Classification of Headache Disorders, 3rd edition (ICHD-3). doi.org/10.1177/0333102417738202
Thunderclap headache and medication-overuse headache.
What next?
- If you live with migraineMigraine and attack triggers
- If the headache came with weakness or trouble speakingStroke: the first hours
This page is for health education and does not replace a doctor’s assessment. If in doubt, get help. Found a mistake? Write to us: contact@thetract.org