What are the differential diagnoses for a headache without a history of trauma?

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Last updated: October 5, 2026 • View editorial policy

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Differential Diagnosis of Non-Traumatic Headache

The differential diagnosis of non-traumatic headache divides into primary headache disorders (migraine, tension-type headache, cluster headache) and secondary headache disorders (life-threatening conditions like subarachnoid hemorrhage, meningitis, cerebral venous thrombosis, and stroke), with the critical first step being identification of red flags that mandate immediate investigation for secondary causes 1.

Primary Headache Disorders

Migraine Without Aura

  • At least 5 attacks lasting 4-72 hours (untreated)
  • At least 2 of these characteristics:
    • Unilateral location (though 40% report bilateral pain)
    • Pulsating quality
    • Moderate to severe intensity
    • Aggravation by routine physical activity
  • At least 1 associated symptom:
    • Nausea and/or vomiting
    • Photophobia AND phonophobia 2, 1, 2

Migraine With Aura

  • At least 2 attacks with fully reversible aura symptoms (visual, sensory, speech/language, motor, brainstem, or retinal)
  • Key differentiating features from TIA:
    • Aura symptoms spread gradually over ≥5 minutes (TIA is sudden and simultaneous)
    • Symptoms occur in succession
    • Each symptom lasts 5-60 minutes
    • Visual aura occurs in >90% of cases (fortification spectra)
    • Sensory symptoms in ~31% (unilateral paresthesia spreading gradually) 1, 2

Tension-Type Headache (TTH)

  • Bilateral location
  • Mild to moderate intensity
  • Pressing or tightening quality (not pulsating)
  • NOT aggravated by routine physical activity
  • Lacks the associated symptoms of migraine (no nausea, no photophobia/phonophobia combination) 1

Cluster Headache

  • Affects only ~0.1% of population
  • Short-lasting attacks: 15-180 minutes
  • Strictly unilateral headache
  • Severe or very severe intensity
  • Ipsilateral cranial autonomic symptoms:
    • Conjunctival injection
    • Lacrimation
    • Nasal congestion 1

Chronic Migraine

  • ≥15 headache days per month for >3 months
  • Fulfills migraine criteria on ≥8 days per month 1

Medication-Overuse Headache (MOH)

  • Headache on ≥15 days per month in someone with pre-existing headache disorder
  • Regular overuse for >3 months of acute headache medications:
    • Non-opioid analgesics on ≥15 days/month, OR
    • Any other acute medication on ≥10 days/month 1

Secondary Headache Disorders (Life-Threatening)

Red Flags Requiring Immediate Investigation

Historical red flags:

  • Thunderclap headache (sudden, maximal intensity at onset)
  • Headache aggravated by physical activity (OR 5.98 for intracranial pathology) 3
  • Age >50 years with new-onset headache (OR 3.0 for intracranial pathology) 3
  • Syncope (OR 5.7 specifically for subarachnoid hemorrhage) 3
  • Progressive worsening pattern
  • Headache worsened by Valsalva maneuver
  • Headache causing awakening from sleep
  • Atypical aura 1

Physical examination red flags:

  • Unexplained fever
  • Focal neurological symptoms
  • Impaired memory
  • Papilledema
  • Abnormal neurological findings 1

Specific Secondary Causes

Subarachnoid Hemorrhage (SAH)

  • Most common intracranial pathology in ED studies (35.1% of secondary headaches)
  • Key predictors: Headache aggravated by physical activity (OR 18.6), syncope (OR 5.7)
  • Important caveat: "Sudden onset" and "worst headache ever" were NOT significant predictors in recent prospective data 3

Ischemic Stroke

  • Second most common (28.1% of secondary headaches in ED cohort) 3

Cerebral Venous Thrombosis (CVT)

  • Headache present in ~90% of cases
  • Typically diffuse, progressive over days to weeks
  • Can present as thunderclap headache (mimicking SAH)
  • Isolated headache without focal signs in up to 25% of cases
  • Associated with papilledema or sixth nerve palsy (mimicking idiopathic intracranial hypertension)
  • Risk factors: pregnancy/postpartum, oral contraceptives, cancer, infection 4

Meningitis

  • Fever, neck stiffness, altered mental status
  • Requires lumbar puncture if suspected 1

Subdural Hemorrhage

  • 10.5% of secondary headaches in ED cohort 3

Sinus Vein Thrombosis

  • 10.5% of secondary headaches in ED cohort 3

Clinical Decision Algorithm

  1. Screen for red flags (see above lists)

    • If present: Neuroimaging (CT or MRI) and/or lumbar puncture indicated 1
    • If absent: Proceed to primary headache diagnosis

  2. For patients without red flags and normal neurological examination:

    • Neuroimaging is NOT warranted for migraine or tension-type headache 5
    • Risk of significant pathology is no greater than in asymptomatic individuals 5

  3. Differentiate primary headaches by:

    • Duration: Migraine 4-72h, TTH variable, Cluster 15-180min
    • Location: Migraine often unilateral, TTH bilateral, Cluster strictly unilateral
    • Quality: Migraine pulsating, TTH pressing/tightening
    • Associated symptoms: Migraine has nausea/photophobia/phonophobia, TTH lacks these, Cluster has autonomic symptoms
    • Activity aggravation: Present in migraine, absent in TTH 1

Critical Pitfalls

  • False reassurance from "normal" presentation: Up to 25% of CVT presents with isolated headache and no focal signs 4
  • Over-reliance on "sudden onset": Recent prospective data shows this is NOT a reliable predictor of SAH 3
  • Missing MOH: Always assess medication use frequency in chronic headache patients 1
  • Unnecessary imaging: In patients with typical primary headache features and normal examination, imaging has extremely low yield and risks false positives 5

References

1
Guideline

diagnosis and management of migraine in ten steps.

Nature Reviews Neurology, 2021

2
Guideline

clinical practice guideline: ménière's disease.

Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2020

5
Guideline

us guidelines on neuroimaging in patients with non-acute headache: a commentary.

Journal of Neurology, Neurosurgery and Psychiatry, 2002

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.