Health LibrarySymptomsHeadache: Red Flags and When to Worry
Symptoms

Headache: Red Flags and When to Worry

Most headaches are benign — but here is what should never be ignored.

Medically reviewed
Updated 2026

The worst-headache-of-your-life rule

A sudden, thunderclap headache reaching peak intensity in seconds can suggest bleeding in the brain and needs an ER visit.

Other red flags

New headache after age 50, headache with fever and stiff neck, headache with vision changes or one-sided weakness.

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Milli's Health Library provides general educational information reviewed against peer-reviewed medical sources. It is not a diagnosis, prescription, or medical advice. Milli does not recommend medications. Always consult a licensed doctor before starting, stopping or changing any treatment.

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