Evaluation of Headache

Last updated: April 8, 2026, 12:42 PM Pacific Time (PDT)

Symptom-first framework for acute or subacute headache. Screen first for thunderclap headache, meningitis/encephalitis, mass effect or elevated intracranial pressure, pregnancy-related vascular causes, temporal arteritis, and acute eye emergencies before settling on a primary headache disorder.

All Immediate red flags Hemorrhage / vascular Pressure / mass / CSF Primary headache Back to Main Page

Interactive diagnostic assistant

Activate the assistant to re-rank likely headache buckets from partial clinical data and suggest a focused workup.
Time course
Red flags
Headache phenotype
Specific secondary clues

Likely diagnoses from entered data

Recommended next labs, imaging, and diagnostics

Flowchart

First pass
Headache is a symptom before it is a diagnosis
Start by deciding whether this headache might be dangerous: thunderclap onset, infection, focal deficit, pregnancy-related vascular disease, mass effect, CSF pressure disorder, temporal arteritis, or an acute eye emergency.
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Immediate red flags
Escalate early when the story is wrong for a routine migraine
A new severe headache with neurologic change, fever, papilledema, pregnancy/postpartum status, age over 50 with visual symptoms, or anticoagulation should move ahead of routine symptomatic treatment.
Hemorrhage / vascular
Thunderclap headache / SAH
RCVS / cervical artery dissection
CVST, especially pregnancy/postpartum or hypercoagulable states
Pressure / mass / CSF
Mass lesion / metastatic disease
Idiopathic intracranial hypertension / intracranial hypertension
Spontaneous intracranial hypotension
Inflammatory / infectious
Meningitis / encephalitis
Temporal arteritis
Sinus / orbital complication if toxic or focal
Primary headache
Migraine with or without aura
Tension-type headache
Cluster / TAC phenotype
Thunderclap
SAH / RCVS / dissection bucket
Thunderclap or abrupt severe onset is not a routine migraine until proven otherwise.
Fever / AMS
Meningitis / encephalitis bucket
Pair fever, meningismus, immunocompromise, or encephalopathy with early infectious workup.
Papilledema / positional
Pressure / mass / CSF bucket
Papilledema, pulsatile tinnitus, Valsalva worsening, progressive course, or orthostatic pattern should redirect toward MRI-based thinking.
Pregnancy
Pregnancy / postpartum vascular bucket
Think preeclampsia, CVST, RCVS, pituitary apoplexy, PRES, or hemorrhage.
Age >50 / visual / eye pain
Temporal arteritis / acute eye emergency
Jaw claudication, vision loss, scalp tenderness, or a red painful eye change management immediately.
No red flags
Primary headache bucket
If the exam is normal and the story is stereotyped for migraine or tension-type headache, routine imaging is usually low yield.

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