Quick answer. A cluster headache is a rare but extremely severe headache causing intense one-sided pain around or behind the eye, usually with a watering, red eye and a blocked or runny nostril on the same side. The attacks come in clusters over weeks, and effective treatments exist, so anyone with this pattern should be assessed by a doctor or neurologist.
A cluster headache is one of the most painful conditions known, causing sudden, severe, one-sided pain around or behind the eye. Although uncommon, it is distinctive: attacks strike in bouts or clusters, often at the same times each day, and are typically accompanied by a watering eye and a blocked or runny nostril on the affected side.
Because the pain is so intense, people with cluster headaches in Singapore often fear something catastrophic is happening, yet the condition is treatable once correctly identified. This guide explains how cluster headaches present, how they differ from migraine, how they are diagnosed and the acute and preventive treatments available, so you know when to seek specialist help.
At a glance
| Feature | Cluster headache | Migraine |
|---|---|---|
| Pain location | Strictly one side, around or behind one eye | Often one side, but can vary |
| Pain duration | 15 minutes to about 3 hours per attack | 4 to 72 hours |
| Pattern | In clusters over weeks, often at set times | Episodic, less rhythmic |
| Eye and nose signs | Watering red eye, drooping lid, blocked nostril | Not typical |
| Behaviour during attack | Restless, agitated, pacing | Prefers to lie still in a dark room |
What is a cluster headache?
A cluster headache is a rare type of primary headache marked by attacks of severe, sharp or burning pain concentrated on one side of the head, usually around or behind a single eye. The name comes from the way attacks group together in clusters, often occurring daily for weeks or months, then easing for a period before returning.
Cluster headaches are far less common than tension headaches or migraine, and they tend to affect adults, more often men, frequently starting in the twenties to forties. While the condition is benign in the sense that it does not damage the brain, the pain is exceptionally severe, which is why prompt and accurate diagnosis matters so that effective treatment can begin.
Symptoms and signs
Cluster headaches have a striking and recognisable pattern. Typical features include:
- Severe, sharp, burning or piercing pain around or behind one eye, always on the same side during a bout
- Attacks lasting from about 15 minutes up to roughly 3 hours
- Several attacks a day, often at predictable times, including waking the person from sleep
- A red, watering eye, drooping or swollen eyelid, and a blocked or runny nostril on the painful side
- Sweating or facial flushing on the affected side
- Restlessness and agitation, with sufferers often pacing rather than lying still
The clustering of attacks over a period of weeks, followed by remission, is the hallmark that distinguishes this condition.
Causes and triggers
The exact cause of cluster headaches is not fully understood, but they are thought to involve the hypothalamus, a region of the brain that helps control body rhythms, which may explain why attacks often occur at the same time of day or night.
During a cluster period, certain factors can trigger an attack, including:
- Alcohol, which is a common and potent trigger during an active bout
- Strong smells, such as solvents or perfume
- Disruption to sleep patterns
There is also often a family tendency. Outside of a cluster period, these triggers usually do not provoke attacks.
How it is diagnosed
Cluster headache is diagnosed mainly from the typical history: the one-sided pain around the eye, the short but intense attacks, the clustering pattern and the accompanying eye and nose symptoms. A doctor will examine you and review your headache pattern carefully.
Because the symptoms can overlap with other conditions, brain imaging such as an MRI scan is often arranged, particularly the first time, to exclude other causes and confirm there is no underlying structural problem. Keeping a record of when attacks occur, how long they last and what accompanies them is very helpful in reaching the diagnosis.
Treatment options
Cluster headaches do not usually respond well to ordinary painkillers, which act too slowly, so specific treatments are used. These fall into two groups:
- Acute treatment to stop an attack quickly, including high-flow oxygen delivered through a mask, and fast-acting triptan medication (often given by injection or nasal spray)
- Preventive treatment taken during a cluster period to reduce the frequency and severity of attacks, which a neurologist will tailor to you
Because the right medication and oxygen need to be arranged and supervised, cluster headache is best managed with specialist input. Avoiding known triggers, particularly alcohol, during an active bout also helps. There is no surgery for typical cluster headache, and treatment is medication-based, so no procedure cost range applies.
When to see a doctor and which specialist
If you have repeated bouts of severe one-sided headache around the eye with a watering eye and blocked nostril, see a doctor so the condition can be correctly identified and effective treatment started. Your GP can make an initial assessment and arrange referral. Because cluster headache needs specific medication and oxygen therapy, most people are referred to a neurologist for diagnosis and ongoing management.
Seek urgent medical care, and call 995 or go to A&E, if a headache is sudden and the worst you have ever had, or comes with fever and a stiff neck, weakness, numbness, slurred speech, confusion, seizures, vision loss, or follows a head injury. These features point to causes other than cluster headache that need emergency assessment. Also see a doctor promptly if your headache pattern changes or steadily worsens.
Related guides
- Best Neurology Clinics in Singapore — our editorial shortlist
- neurology clinics directory
- Costochondritis
- OGTT Test
- Tension Headache
- Retinal Detachment
- Uveitis
Sources
- NHS – Cluster Headaches
- Mayo Clinic – Cluster Headache
- HealthHub Singapore – Headache
- NHS – Triptans
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