What are the red flags for headache?

The SNOOP mnemonic covers them: Systemic symptoms or risk factors, Neurologic symptoms, sudden thunderclap Onset, Older age at onset (over 50), and a Pattern change, including headaches brought on by coughing or straining or that change with position.

What questions should I ask in a headache history?

Ask how quickly it reached its worst, whether it is new or the usual headache, where it is, what it feels like, how long it lasts, what makes it worse, and about nausea, light sensitivity, visual or neurologic symptoms, fever and neck stiffness. Then ask how often the patient takes painkillers.

How do you tell migraine from tension-type headache?

Migraine is usually one-sided, throbbing, moderate to severe, worse with activity, and comes with nausea or sensitivity to light and sound. Tension-type headache is usually on both sides, pressing like a tight band, milder, not worse with activity, and without nausea.

What is a thunderclap headache?

A severe headache that reaches its maximum within about a minute. It needs urgent assessment for subarachnoid hemorrhage and other vascular causes.

Updated November 10, 2026

Headache history: red flags and how to tell the types apart

Most headaches are primary: migraine, tension-type or cluster headache. The history's first job is to find the few that are secondary to something serious, such as subarachnoid hemorrhage, meningitis, a mass or giant cell arteritis. Its second is to tell the primary headaches apart, which it can usually do on its own.

Characterize the headache

Onset: "How quickly did it reach its worst?" A headache that peaks within a minute is a thunderclap headache until proven otherwise.
Is this new, or the usual headache? "Have you had headaches like this before?" A change in a long-standing pattern matters.
Site: one side or both, behind one eye, the back of the head
Character: throbbing, pressing like a tight band, stabbing
Duration and frequency, and the time of day it is worst
Aggravating factors: movement, coughing, straining, lying down, bright light
Associated symptoms: nausea and vomiting, sensitivity to light or sound, visual disturbance, weakness or numbness, fever, neck stiffness, a rash

Red flags: SNOOP

Systemic: Fever, weight loss, or a background of cancer, HIV or immunosuppression.
Neurologic: Confusion, weakness, numbness, double vision, loss of consciousness or a seizure.
Onset: Sudden, thunderclap onset, maximal within a minute: subarachnoid hemorrhage until proven otherwise.
Older: A new headache after the age of 50: consider giant cell arteritis and a mass.
Pattern change: Progressive headache, a change in the usual pattern, or a headache brought on by coughing, straining or exertion, or that changes with position.

Telling the primary headaches apart

Migraine: One-sided, pulsating, moderate to severe, worse with routine activity, with nausea or sensitivity to light and sound, lasting 4 to 72 hours. About a third of patients have an aura, usually visual, lasting under an hour before the pain.
Tension-type headache: Both sides, pressing or tightening like a band, mild to moderate, not worse with activity, without nausea.
Cluster headache: Severe pain around one eye or temple, lasting 15 minutes to 3 hours, with a watering, red eye and a blocked nose on the same side, and restlessness. Attacks come in bouts of weeks, often at the same time each night.
Medication overuse headache: A daily or near-daily headache in someone taking painkillers on 10 to 15 or more days a month. Ask exactly how often they take them.

Secondary causes to ask about

Subarachnoid hemorrhage: Thunderclap onset, often described as the worst headache of their life, sometimes with collapse, vomiting or neck stiffness.
Meningitis: Headache with fever, neck stiffness, sensitivity to light, and sometimes a rash or confusion.
Raised intracranial pressure: Worse in the morning, on lying down and on coughing or straining, with vomiting or visual disturbance.
Giant cell arteritis: Over 50, with a temporal headache, scalp tenderness, pain in the jaw on chewing, and visual symptoms. It can cause permanent blindness, so it is treated urgently.
Carbon monoxide poisoning: Headache that improves away from home, or that others in the household share.

Background

Painkiller use: what, how much, how many days a month
Contraception: estrogen-containing contraception is usually avoided in migraine with aura, because of stroke risk
Pregnancy or recent delivery: preeclampsia, cerebral venous thrombosis
Head injury, recent or remote
Family history of migraine or of subarachnoid hemorrhage
Triggers: sleep, stress, missed meals, alcohol, the menstrual cycle

Frequently asked questions

What are the red flags for headache?: The SNOOP mnemonic covers them: Systemic symptoms or risk factors, Neurologic symptoms, sudden thunderclap Onset, Older age at onset (over 50), and a Pattern change, including headaches brought on by coughing or straining or that change with position.
What questions should I ask in a headache history?: Ask how quickly it reached its worst, whether it is new or the usual headache, where it is, what it feels like, how long it lasts, what makes it worse, and about nausea, light sensitivity, visual or neurologic symptoms, fever and neck stiffness. Then ask how often the patient takes painkillers.
How do you tell migraine from tension-type headache?: Migraine is usually one-sided, throbbing, moderate to severe, worse with activity, and comes with nausea or sensitivity to light and sound. Tension-type headache is usually on both sides, pressing like a tight band, milder, not worse with activity, and without nausea.
What is a thunderclap headache?: A severe headache that reaches its maximum within about a minute. It needs urgent assessment for subarachnoid hemorrhage and other vascular causes.