Cluster headaches - concise ED revision
Definition
Cluster headache is a primary headache disorder of strictly unilateral, extremely severe periorbital/retro‑orbital pain occurring in discrete bouts (“clusters”), with prominent ipsilateral cranial autonomic features and a strong circadian pattern. Attacks are stereotyped for the patient and require rapid, area‑specific acute therapy (NICE CG150).
Epidemiology and risk factors
- More common in men; typical onset in young adulthood. Historical male:female ratios were high but more recent series show smaller differences.
- Strong association with cigarette smoking.
- Alcohol commonly provokes attacks during a cluster period.
- Two clinical forms:
- Episodic (most common) with remission periods.
- Chronic with little or no remission.
Typical clinical features
- Pain: very severe, strictly unilateral, periorbital/retro‑orbital; often described as boring, sharp or burning.
- Duration and frequency: untreated attacks usually last 15-180 minutes and may occur 1-8 times per day.
- Timing: attacks often recur at the same time each day and frequently at night.
- Behaviour: patients are restless or agitated during attacks (pacing, rocking), which helps distinguish cluster headache from migraine.
- Ipsilateral cranial autonomic signs: conjunctival injection, lacrimation, nasal congestion or rhinorrhoea, ptosis and/or miosis (Horner‑like features).