What are the different types of headaches?

Types of Headache

Headaches are broadly classified into primary and secondary types, with primary headaches being disorders without underlying medical conditions and secondary headaches resulting from specific underlying causes.

Primary Headache Disorders

Primary headaches account for approximately 98% of all headache cases and are categorized into four main groups according to the International Classification of Headache Disorders (ICHD-3) 1:

1. Migraine

   • Affects approximately 12% of the population 2
   • Diagnostic criteria:
     • Recurrent attacks lasting 4-72 hours
     • At least two characteristics: unilateral location, pulsating quality, moderate-severe intensity, aggravation by physical activity
     • At least one associated symptom: nausea/vomiting or photophobia and phonophobia
   • Subtypes:
     • Migraine without aura
     • Migraine with aura (includes visual, sensory, speech/language, motor, brainstem, or retinal symptoms)
     • Chronic migraine (≥15 headache days/month for >3 months, with ≥8 days meeting migraine criteria)

2. Tension-Type Headache

   • Most common primary headache (38% of population) 2
   • Characterized by:
     • Bilateral, pressing/tightening quality
     • Mild to moderate intensity
     • Not aggravated by routine physical activity
     • No nausea/vomiting (mild photophobia or phonophobia may be present)

3. Trigeminal Autonomic Cephalalgias (TACs)

   • Include:
     • Cluster headache: Severe unilateral orbital/temporal pain with ipsilateral autonomic features
     • Paroxysmal hemicrania: Similar to cluster but shorter, more frequent attacks
     • Short-lasting unilateral neuralgiform headache attacks (SUNCT/SUNA)
     • Hemicrania continua: Continuous unilateral headache with autonomic features

4. Other Primary Headaches

   • Include:
     • Primary stabbing headache
     • Primary cough headache
     • Primary exercise headache
     • Primary thunderclap headache
     • Cold-stimulus headache
     • External pressure headache
     • Primary sex headache
     • Hypnic headache
     • New daily persistent headache

Secondary Headache Disorders

Secondary headaches are symptoms of underlying conditions and require prompt identification of "red flags" 1:

1. Vascular Disorders

   • Subarachnoid hemorrhage (thunderclap headache)
   • Stroke/TIA
   • Arterial dissection
   • Venous sinus thrombosis

2. Intracranial Pressure Abnormalities

   • Idiopathic intracranial hypertension (pseudotumor cerebri)
   • Spontaneous intracranial hypotension
   • Post-lumbar puncture headache

3. Infectious Causes

   • Meningitis
   • Encephalitis
   • Sinusitis

4. Neoplastic Causes

   • Brain tumors
   • Metastatic disease

5. Trauma-Related

   • Post-traumatic headache
   • Subdural hematoma

6. Substance-Related

   • Medication overuse headache (≥15 days/month for NSAIDs, ≥10 days/month for triptans)
   • Substance withdrawal

7. Non-Vascular Intracranial Disorders

   • Seizure-related headache
   • CSF disorders

8. Disorders of Homeostasis

   • Hypoxia/hypercapnia
   • Dialysis headache

Red Flags Requiring Immediate Attention

Critical warning signs that may indicate life-threatening conditions 1:

• Thunderclap headache (sudden onset, maximal intensity within seconds to minutes)
• Focal neurological deficits (weakness, numbness, visual changes, speech difficulties)
• Altered mental status or level of consciousness
• Neck stiffness or meningismus
• Headache following head trauma
• Fever with headache
• New headache in patients ≥50 years
• Headache in immunocompromised patients or those with cancer
• Headache worsened by Valsalva maneuver, causing awakening from sleep
• Rapidly increasing frequency or severity of headache

Diagnostic Approach

For suspected secondary headaches, appropriate imaging is essential 3, 1:

• Thunderclap headache/suspected SAH: Immediate non-contrast head CT (98% sensitivity)
• Suspected stroke/vascular abnormality: MRI with MRA/MRV preferred
• Suspected infection: MRI brain with contrast; consider lumbar puncture for meningitis
• Negative imaging but high clinical suspicion: Lumbar puncture to rule out SAH or meningitis

For primary headaches, diagnosis is primarily clinical based on ICHD-3 criteria, with neuroimaging rarely contributing to evaluation 3, 2.

Common Diagnostic Pitfalls

• Failure to obtain neuroimaging for patients with red flag symptoms 1
• Dismissing sentinel headaches (may occur 2-8 weeks before major SAH rupture) 1
• Misdiagnosing migraine with cranial autonomic symptoms as "sinus headache" 3
• Failure to recognize chronic migraine or medication overuse headache 1

By understanding these classifications and recognizing warning signs, clinicians can appropriately diagnose headache disorders and initiate proper management to reduce morbidity and improve quality of life.