What are the steps to diagnose migraine?

How to Diagnose Migraine

Migraine diagnosis is primarily clinical, based on a detailed medical history and systematic application of the International Classification of Headache Disorders-3 (ICHD-3) criteria, with physical examination serving as confirmation and neuroimaging reserved only for suspected secondary causes. 1, 2

Step 1: Obtain a Comprehensive Headache History

Document the following essential elements to apply ICHD-3 criteria systematically 1:

• Age at onset: Migraine typically begins at or around puberty 1, 2
• Duration of episodes: Migraine attacks last 4-72 hours (untreated or unsuccessfully treated) 1, 3
• Frequency: Episodic (<15 days/month) versus chronic (≥15 days/month for >3 months) 2, 3
• Pain location: Unilateral location (though can be bilateral) 2, 3
• Pain quality: Pulsating or throbbing character 2, 3
• Pain severity: Moderate to severe intensity 1, 3
• Aggravating factors: Worsening with routine physical activity (walking, climbing stairs) 1, 2
• Accompanying symptoms: Nausea and/or vomiting, photophobia (light sensitivity), phonophobia (sound sensitivity) 1
• Aura symptoms: Visual disturbances (flashing lights, zigzag lines), hemisensory symptoms (numbness, tingling), speech/language difficulties lasting 5-60 minutes 1, 2
• Medication history: Current and past use of acute and preventive medications, including frequency of use 1
• Family history: Migraine has strong genetic component; positive family history strengthens diagnosis 2, 3

Step 2: Apply ICHD-3 Diagnostic Criteria

Migraine Without Aura 2, 3

Requires at least 5 lifetime attacks with all of the following:

• Headache lasting 4-72 hours (untreated or unsuccessfully treated)
• At least 2 of these pain characteristics:
  • Unilateral location
  • Pulsating quality
  • Moderate or severe intensity
  • Aggravation by routine physical activity
• At least 1 of these accompanying symptoms:
  • Nausea and/or vomiting
  • Photophobia AND phonophobia (both must be present)

Migraine With Aura 2, 3

Requires at least 2 attacks with:

• One or more fully reversible aura symptoms (visual, sensory, speech/language, motor, brainstem, or retinal)
• At least 3 of these characteristics:
  • At least one aura symptom spreads gradually over ≥5 minutes
  • Two or more aura symptoms occur in succession
  • Each aura symptom lasts 5-60 minutes
  • At least one aura symptom is unilateral
  • At least one aura symptom is positive (flashing lights, tingling)
  • Aura accompanied by or followed by headache within 60 minutes

Chronic Migraine 2, 3

Requires all of the following:

• Headache on ≥15 days/month for >3 months
• Patient has had at least 5 attacks fulfilling criteria for migraine without aura or with aura
• On ≥8 days/month for >3 months, headache meets migraine criteria or is believed by patient to be migraine and relieved by triptan/ergot derivative

Step 3: Use Diagnostic Aids to Confirm Diagnosis

Screening Questionnaires 1, 2

ID-Migraine (3-item questionnaire): Sensitivity 0.81, specificity 0.75, positive predictive value 0.93 2

• Questions assess headache-associated nausea, photophobia, and disability
• Positive screen requires confirmation with full history

Migraine Screen Questionnaire (MS-Q, 5-item): Sensitivity 0.93, specificity 0.81, positive predictive value 0.83 2

• Includes questions on frequency, intensity, duration, nausea, photophobia, phonophobia, and disability

Headache Diary 1, 2

Essential for accurate diagnosis and reducing recall bias:

• Document pattern and frequency of headaches
• Record accompanying symptoms (nausea, photophobia, phonophobia)
• Track acute medication use (critical for identifying medication-overuse headache)
• Note triggers and menstrual cycle relationship
• If diary entries consistently fail to meet ICHD-3 criteria over multiple attacks, migraine is ruled out 2

Step 4: Perform Physical and Neurological Examination

Physical examination is most often confirmatory rather than diagnostic 1. The neurological examination should be normal in primary migraine; any focal neurological findings suggest secondary causes requiring investigation 2.

Step 5: Screen for Red Flags Requiring Investigation

Do NOT routinely order neuroimaging for typical migraine presentations. 2 Investigations are only indicated when red flags suggest secondary causes 1, 2:

Red Flags Requiring Urgent Investigation 2

• Thunderclap headache ("worst headache of life") → Non-contrast CT head if <6 hours from onset (sensitivity 95% day 0,74% day 3,50% at 1 week) 2
• New-onset headache after age 50 → ESR/CRP for giant cell arteritis (note: ESR normal in 10-36% of cases) 2
• Progressive worsening headache → MRI brain with and without contrast (preferred modality) 2
• Headache awakening patient from sleep → MRI to exclude space-occupying lesion 2
• Headache with Valsalva, cough, or exertion → MRI to exclude increased intracranial pressure 2
• Focal neurological symptoms/signs → MRI brain 2
• Unexplained fever with neck stiffness → Consider lumbar puncture for meningitis 2
• Recent head/neck trauma → CT head acutely 2
• Altered consciousness, memory, or personality → Emergency evaluation 2

Step 6: Identify Probable Migraine and Medication-Overuse Headache

Probable Migraine 1

When attacks are "migraine-like" but missing one feature required for full ICHD-3 criteria, diagnose as probable migraine pending confirmation during early follow-up 1. The ICHD-3 criteria prioritize specificity over sensitivity, so this category captures patients who likely have migraine but need further observation 1, 3.

Medication-Overuse Headache 2

Critical pitfall: Overuse of acute medications transforms episodic migraine into chronic daily headache 2. Suspect when:

• Headache on ≥15 days/month
• Regular overuse of non-opioid analgesics (aspirin, acetaminophen, NSAIDs) on ≥15 days/month for ≥3 months 2
• OR any other acute medication (triptans, ergots, opioids, combination analgesics) on ≥10 days/month for ≥3 months 2

This requires different management (medication withdrawal) and rules out simple episodic migraine 2.

Common Diagnostic Pitfalls

Do not conflate headache diaries with headache calendars: Diaries contain detailed information about each attack (essential for diagnosis), while calendars simply track frequency and are used for follow-up monitoring 1.

Do not assume unilateral pain is required: While unilateral location increases likelihood of migraine, bilateral migraine is common, especially in children and adolescents 3.

Do not miss chronic migraine: Patients with ≥15 headache days/month have substantially greater burden and require different treatment (preventive therapy is mandatory) 2, 3.

Do not order routine neuroimaging: MRI or CT is not indicated for typical migraine presentations without red flags; imaging should only be performed when secondary causes are suspected 2, 4.