Headache
A headache is pain or discomfort felt in any region of the head, scalp, or neck. It is one of the most common neurological complaints in clinical practice.
Classification (ICHD-3)
The International Classification of Headache Disorders, 3rd edition (ICHD-3) divides headaches into two broad categories (Management of Headache, p. 6):
1. Primary Headache Disorders
These are idiopathic, recurrent, and stereotyped — meaning there is no identifiable underlying structural or systemic cause. They are disorders in their own right. Major types include:
| Type | Key Features |
|---|
| Migraine | Unilateral, throbbing pain; often with nausea, photophobia, phonophobia; may have aura |
| Tension-type headache (TTH) | Bilateral, pressure/tightening quality; mild-moderate intensity; most common type overall |
| Cluster headache | Severe, unilateral periorbital pain; autonomic features (tearing, nasal congestion); occurs in clusters |
| Other primary headaches | Includes exertional, cough, hypnic, and thunderclap headaches (without secondary cause) |
2. Secondary Headache Disorders
These headaches are caused by an underlying condition (Management of Headache, p. 6). Common causes include:
- Intracranial: meningitis, subarachnoid hemorrhage, brain tumor, increased intracranial pressure
- Vascular: cerebral venous thrombosis, stroke, giant cell arteritis
- Systemic/metabolic: hypertension, infections (fever), CO poisoning, medications/substances
- Structural: cervicogenic headache, sinusitis, glaucoma
Diagnosis
Diagnosis of primary headache disorders is clinical, based on history and criteria from the ICHD-3. Key elements of evaluation include:
- Onset: sudden ("thunderclap") vs. gradual
- Location: unilateral vs. bilateral
- Quality: throbbing, pressure, stabbing
- Duration and frequency
- Associated symptoms: nausea, visual changes, autonomic features
- Triggers and relieving factors
- Neurological examination
Red flags ("SNOOP4") requiring urgent investigation:
- Systemic symptoms/signs
- Neurological deficits
- Onset sudden/severe (worst headache of life)
- Older age (>50, new headache)
- Progressive worsening
- Postural component
- Precipitated by Valsalva
- Papilledema
Management
Management is tailored to headache type, severity, and the individual patient (Acute Treatment of Migraine in Children and Adolescents, p. 2):
- Acute/abortive therapy: analgesics (NSAIDs, acetaminophen), triptans (for migraine), ergotamines, oxygen (for cluster headache)
- Preventive therapy: beta-blockers, tricyclics, valproate, topiramate, CGRP monoclonal antibodies (for frequent migraines)
- Behavioral/lifestyle: stress management, sleep hygiene, hydration, trigger avoidance, biofeedback
Key Takeaway
Most headaches encountered in practice are primary (especially tension-type and migraine) and are benign, though disabling. The clinical priority is to rule out secondary causes, particularly life-threatening ones, before attributing a headache to a primary disorder.