Cluster Headache

Cluster headache is a neurologic condition characterized by short-lasting but extremely severe headache attacks, usually centered around one eye or temple, and accompanied by eye and nasal symptoms on the same side.

Attacks tend to occur in clusters (bouts) lasting weeks to months, often followed by long symptom-free periods.

Cluster headache is sometimes called the “suicide headache” due to its intensity, but effective treatments exist.

Cluster headache and migraine are often confused, and are distinguished by their duration of attacks, presence of side-locked pain, presence of autonomic symptoms, and the behaviour during attacks.

1) Duration of attacks

• Cluster headache:

  • Lasts 15 to 180 minutes (up to ~3 hours)

  • Can occur 1–8 times per day

• Migraine:

  • Lasts 4 to 72 hours (if untreated)

2) Side-locked pain (same side every time)

• Cluster headache:

  • Pain is strictly one-sided

  • Almost always stays on the same side during a cluster

• Migraine:

  • Can be one-sided but often switches sides or becomes bilateral

3) Cranial autonomic symptoms (eye and nose symptoms)

Cluster headache almost always includes symptoms on the same side as the pain, such as:

• Red or tearing eye

• Drooping eyelid or smaller pupil

• Nasal congestion or runny nose

• Facial flushing or sweating

Migraine may have some overlap, but cluster headache has more prominent and consistent autonomic symptoms.

4) Restlessness and agitation

• Cluster headache:

  • People feel agitated, restless, paced, or unable to lie still

• Migraine:

  • People usually want to lie still in a dark, quiet room

This behavioral difference is one of the most reliable clinical clues.

Symptoms checklist:

You may have cluster headache if your attacks:

• Are very severe and short-lasting

• Occur multiple times per day

• Always affect the same side

• Cause eye redness, tearing, or nasal symptoms

• Make you feel restless or unable to lie down

• Episodic cluster headache:

  • Attacks occur in bouts with remission periods ≥3 months

• Chronic cluster headache:

  • Attacks persist for >1 year with little or no remission

Treatment strategies may differ slightly based on type.

Cluster headache requires fast-acting treatment. Oral medications are often too slow.

Sumatriptan

Sumatriptan is highly effective for cluster headache when given as:

• Subcutaneous injection (fastest and most reliable)

Nasal spray may help some people, but oral tablets are often too slow for cluster attacks.

High-flow oxygen

High-flow 100% oxygen is one of the most effective treatments for an acute cluster headache attack.

How it is used:

• Delivered through a non-rebreather mask

• Typically at high flow (12–15 L/min)

• Used for 10–15 minutes at the start of an attack

Oxygen is:

• Non-sedating

• Non-addictive

• Safe for repeated use

What to do during an attack (step-by-step)

1. Start oxygen immediately at high flow

2. Use injectable sumatriptan if prescribed

3. Avoid lying flat if restlessness is severe

4. Track attack timing and response (consider using a tracker like MyCusters)

First-line preventive: Verapamil

Verapamil is the most commonly used and most effective preventive medication for cluster headache.

Key points:

• Dose often needs to be increased gradually

• ECG monitoring is required (to ensure heart rhythm safety)

• Often started early in a cluster period

Verapamil is considered the standard first-line preventive.

Second-line option: Lithium (less preferred)

Lithium can be effective, especially in chronic cluster headache, but:

• Requires blood level monitoring

• Has more potential side effects

• Is generally used when verapamil is not tolerated or ineffective
  
  

CGRP-targeted therapy: Galcanezumab

Galcanezumab is a CGRP monoclonal antibody approved for episodic cluster headache.

It has been shown to:

• Reduce attack frequency early in treatment

• Be generally well tolerated

It is an option when standard preventives are insufficient or not tolerated.

What is bridge therapy?

Bridge therapy is a temporary treatment used to rapidly reduce attack frequency while waiting for preventive medication to take effect.

Prednisone (short course)

A short course of prednisone (steroid) may:

• Rapidly suppress cluster attacks

• Be used for days to weeks only

Steroids are not a long-term solution due to side effects, but can be very effective as a bridge.

Occipital nerve block

A greater occipital nerve block is a targeted injection that can:

• Reduce attack frequency

• Provide temporary relief during a cluster

• Help bridge until preventives work

You should seek specialist evaluation if:

• Headache attacks are short, severe, and one-sided

• You have eye or nasal symptoms with pain

• Standard migraine treatments are ineffective

• Attacks occur multiple times per day

Early diagnosis leads to faster relief and better outcomes.