Cluster headache: diagnosis and treatment

Cluster headache is severe unilateral orbital pain lasting 15–180 minutes with ipsilateral autonomic signs or restlessness; treat attacks with high-flow oxygen or a fast triptan, and use oxygen when triptans are contraindicated.

1. ICHD-3 defines the attack. At least five attacks of severe unilateral orbital, supraorbital or temporal pain lasting 15–180 minutes untreated, with ipsilateral autonomic features and/or restlessness, from every other day to 8 a day. During the worst attacks pain is excruciating, and patients usually cannot lie down ¹.
2. Autonomic signs are ipsilateral. They include conjunctival injection or lacrimation, nasal congestion or rhinorrhea, eyelid edema, facial sweating, and miosis or ptosis ¹.
3. Bouts and remissions define the episodic form. Attacks cluster in periods of weeks or months, usually on the same side within a period, separated by remissions usually lasting months or years; 10–15% have chronic cluster headache without such remissions ¹.
4. Three acute treatments are Level A. The AHS guideline gives Level A to subcutaneous sumatriptan, zolmitriptan nasal spray and high-flow oxygen ².
5. Oxygen works fast. In a randomized crossover trial, 100% oxygen at 12 L/min by face mask for 15 minutes made 78% of attacks pain-free at 15 minutes versus 20% with air ³.
6. Suboccipital steroid is the Level A preventive. Suboccipital steroid injection is the only preventive with a Level A recommendation in the 2016 AHS guideline ².

Sumatriptan is contraindicated with coronary artery disease or vasospasm, prior stroke or TIA, peripheral vascular disease and uncontrolled hypertension; high-flow oxygen is the Level A acute alternative without these cardiovascular limits ²⁴.

• Subcutaneous sumatriptan for cluster headache is a single 6 mg dose; maximum 12 mg in 24 hours, at least 1 hour apart ⁴.
• Sphenopalatine ganglion stimulation received a Level B recommendation for acute treatment ².
• Deep brain stimulation had a negative study (Level B); warfarin a positive study (Level C) ².
• Men are affected about three times as often as women, and onset is usually at age 20–40 ¹.
• Acute attacks involve activation of the posterior hypothalamic gray matter ¹.
• About 5% of cluster headache may be autosomal dominant ¹.
• During a cluster period, attacks may be provoked by alcohol, histamine or nitroglycerin ¹.

• Using low-flow oxygen; the trial used 100% oxygen at 12 L/min by face mask at attack onset ³.
• Giving sumatriptan to a patient with coronary disease or recent ergot use ⁴.
• Confusing cluster headache with paroxysmal hemicrania, whose attacks are shorter and indomethacin-responsive ⁵.