What is the initial approach to diagnosing and managing an unspecified headache?

Initial Approach to Diagnosing Unspecified Headache

Begin by obtaining a detailed medical history focusing on age at onset, duration, frequency, pain characteristics (location, quality, severity, aggravating/relieving factors), accompanying symptoms (photophobia, phonophobia, nausea, vomiting), aura symptoms, and medication use—this history is the mainstay of diagnosis and enables systematic application of ICHD-3 criteria. 1

Immediate Red Flag Assessment

Before proceeding with primary headache diagnosis, you must actively exclude dangerous secondary causes by screening for these specific red flags:

• Recent head or neck trauma 2, 3
• New, worse, worsening, or abrupt-onset headache (especially "worst headache of life") 2, 4, 3
• Headache brought on by Valsalva maneuver, cough, or exertion 2, 3
• Age over 50 years with new headache 5, 2, 3
• Focal neurologic signs or symptoms 5, 4
• Papilledema or neck stiffness 4
• Systemic signs/symptoms or immunocompromised state 2, 4, 3
• Personality changes 4
• Pregnancy 2
• History of cancer or HIV infection 2, 3

Neuroimaging Decisions

If any red flags are present, obtain neuroimaging immediately—use non-contrast head CT in acute/emergency settings for suspected hemorrhage, but prefer brain MRI with and without contrast when available for superior detection of masses, ischemia, and structural abnormalities. 5

• If CT/MRI is normal but subarachnoid hemorrhage remains suspected, perform lumbar puncture for CSF analysis 5
• Lower your threshold for neuroimaging in patients over 50, even without classic red flags 5
• If intracranial hemorrhage is suspected specifically, head CT without contrast is the recommended study 4

Systematic Differential Diagnosis

Once secondary causes are excluded, apply ICHD-3 criteria to differentiate primary headache types:

Migraine Without Aura

Requires at least 5 attacks with all of the following 1, 6:

• Duration: 4-72 hours when untreated 1, 6
• At least 2 pain characteristics:
  • Unilateral location 1
  • Pulsating/throbbing quality 1
  • Moderate to severe intensity 1
  • Worsening with routine physical activity 1
• At least 1 accompanying symptom:
  • Nausea and/or vomiting 1
  • Photophobia AND phonophobia 1

Suspect migraine particularly if pain is unilateral and/or pulsating with accompanying photophobia, phonophobia, nausea, or vomiting. 1

Migraine With Aura

Requires at least 2 attacks with completely reversible aura symptoms (visual, sensory, language, motor, brainstem, or retinal) that typically spread gradually over ≥5 minutes and occur in succession—this differentiates from TIA, which has sudden, simultaneous onset. 1, 7, 6

Note that migraine with aura and migraine without aura commonly coexist in the same patient—diagnose both when present. 1

Chronic Migraine

Diagnose chronic migraine when headache occurs ≥15 days per month for >3 months, with migraine features on ≥8 days per month. 1, 5, 6

Tension-Type Headache

Requires at least 2 of the following 1, 5:

• Bilateral location 1, 5
• Pressing/tightening (non-pulsatile) character 1, 5
• Mild to moderate intensity 1, 5
• No aggravation with routine activity 1, 5

AND both of the following:

• No nausea or vomiting (anorexia may be present) 1
• No photophobia AND phonophobia (may have one or the other) 1

Cluster Headache

Requires 5 attacks with frequency of 1-8 attacks per day, featuring 1:

• Severe unilateral orbital, supraorbital, or temporal pain lasting 15-180 minutes untreated 1
• At least 1 ipsilateral autonomic feature:
  • Lacrimation 1
  • Nasal congestion or rhinorrhea 1
  • Forehead/facial sweating 1
  • Ptosis, miosis, or eyelid edema 1

Cervicogenic Headache

Suspect when associated neck pain and restricted cervical range of motion are present, though recognize that imaging findings (disc bulges, degenerative changes) do not differentiate symptomatic from asymptomatic patients. 5

Cervical Radiculopathy

Look for neuropathic pain radiating into upper extremity following dermatomal distribution, with focal neurological symptoms including weakness, sensory changes, or reflex abnormalities. 5

Diagnostic Aids

Implement headache diaries immediately to record pattern and frequency of headaches, accompanying symptoms (nausea, photophobia, phonophobia), and acute medication use—these are essential for diagnosis confirmation and ongoing management. 1, 6

Consider using validated screening questionnaires:

• ID-Migraine (3 questions): Identifies migraine based on headache-associated nausea, photophobia, and disability 1
• Migraine Screen Questionnaire (MS-Q, 5 questions): Screens for frequency, intensity, length, associated symptoms, and disability 1, 6

Critical Pitfalls to Avoid

Do not assume primary headache disorder without thorough evaluation for secondary causes, especially in patients over 50. 5

Monitor for medication overuse headache: triptans/ergots/combination analgesics ≥10 days/month for ≥3 months, or simple analgesics ≥15 days/month for ≥3 months. 5

Recognize that ICHD-3 criteria prioritize specificity over sensitivity—use "probable migraine" diagnosis when attacks miss one feature required for full criteria, then confirm during early follow-up. 1, 6

Strengthen suspicion of migraine when family history is positive and onset occurred at or around puberty. 1, 6

When to Refer

Refer to specialist for chronic migraine after initial evaluation, headache of uncertain diagnosis, or poor response to initial management. 5