Headaches cost the British economy around £1.5bn a year. Photograph: Nick Veasy/Getty Images
We all know what it's like to have a headache. They can turn the best of occasions into a form of torture. Four out of five people get tension headaches. One in seven experience migraines. Headaches cost the economy around £1.5bn a year through lost work days. Trouble is, while some causes of headaches are obvious – such as when you've had too many glasses of wine the night before – others are more tricky to call. And how can you tell what's serious and what isn't? A good starting point is knowing what type of headache you have.
Tension headache
Tension headaches tend to feel like a pressure or tightness around the head. They can last for only half an hour or up to a week. This is the most common type of headache and most people will have had one. Tension headaches can be stress-related or due to problems with the muscles in the neck and face, but there is often no obvious cause. Most people who get tension headaches don't get them very often but around 3% of the population get them regularly, on average every other day. Ibuprofen or paracetamol are usually effective, and exercise helps too. For regular headaches preventative treatment with amitriptyline is available. Although better known as an antidepressant, amitriptyline doesn't prevent headaches by making you happier, although why exactly it does work is still not known.
Migraine
Migraine causes recurrent headaches on one side of the head that last for more than four hours. It is common to feel sick and sitting in a dark room often helps. A quarter to a third of migraine sufferers get an "aura" before the headache begins. This is not a supernatural glow around the body, but unusual sensations such as pins and needles, seeing bright lights, or feeling distant from people around you.
A recent survey found that a third of people who work with a migraine sufferer are suspicious that migraine is used as an excuse for days off work. Perhaps we should be more sympathetic: the World Health Organisation has ranked a day with severe migraine as disabling as a day with quadriplegia, psychosis or dementia. It is not a psychological illness: "Migraine is very clearly a brain disorder," says Dr Paul Shanahan, consultant neurologist at the Headache Group, National Hospital for Neurology and Neurosurgery in London. "There are changes in activity of certain brain regions which occur during an acute migraine attack that give rise not just to pain, but a wide variety of symptoms. It's not 'just a headache', and it's certainly not psychological."
The mechanism underlying a migraine has been the subject of much debate over the years. Researchers used to think that the aura was caused by blood vessels in the brain narrowing. Then the vessels widen, which was thought to cause the headache. However, more recent research shows that blood flow changes may be a consequence of unusual brain activity rather than the initial cause of the migraine. During an aura, a wave of electrical activity travels slowly (at only a few millimetres per minute) across the surface of the brain. This can trigger a variety of symptoms including visual disturbance, pins and needles, speech difficulties and limb weakness. The way the brain processes sensations becomes disordered so that movement, lights, sounds and even smells become harder to tolerate.
Avoiding triggers can be useful so keeping a headache diary can help. However, only 20% of migraine sufferers have a dietary trigger. The British Association for the Study of Headache (Bash) guidelines warn that "too much effort in seeking triggers causes introspection and may be counter-productive." If migraine can't be relieved by over-the-counter painkillers such as ibuprofen, triptans can help. Triptans can abort migraine attacks by mimicking the effect of the neurotransmitter serotonin at nerve receptors.
Cluster headache
Cluster headaches cause severe throbbing pain on one side of the face around the eye. Each headache lasts for up to four hours and is often accompanied by a red eye, tears and a runny nose.
The pain can be unbearable. "Cluster headaches have been described as the most severe form of pain a human can experience," says Shanahan. "Occasionally patients can be driven to suicide by the severity and relentlessness of the pain, hence their description as 'suicide headaches'."
The name derives from their tendency to occur in clusters, often occurring at the same times every day. "These cycles can run for weeks, months or even years, and point to the brain's 'body clock' as having a role in the condition," says Shanahan.
Oxygen therapy (breathing pure oxygen through a mask for 20 minutes or more) is one of the best treatments for cluster headache and is available on prescription. However, not enough people are getting this, or other effective treatments such as sumatriptan injections, according to Shanahan. "These treatments for cluster headache are under-utilised, and, frustratingly, we see patients who are undertreated while having excruciating daily pain."
Hangover
The exact cause of a hangover headache isn't known but there are plenty of likely culprits: alcohol causes blood vessels in the brain to widen and can alter the effects of serotonin on nerve endings – both of which occur in migraine. Alcohol also causes dehydration, a common trigger of migraine attacks. Fortunately the pain usually goes after some paracetamol and a good night's sleep but some may have migraine without realising it, according to Shanahan. "People who get headaches when thirsty may well have migraine, as do many people who get bad hangovers after fairly modest amounts of alcohol. Alcohol is often a very potent trigger for cluster headache, as well."
Medication overuse headache
Paradoxically, all painkillers can cause a headache if taken regularly over a long period of time. Medication overuse headache is difficult to tell apart from the original headache so it can be very difficult to diagnose. Anyone who takes codeine or triptan-based drugs for more than 10 days a month or other over-the-counter remedies such as paracetamol or ibuprofen for 15 days a month is at risk.
The only treatment is to stop taking the painkillers. The headache often gets worse initially, and improvement may only be seen between a week and a month later.
Brain tumour
Fewer than 4% of brain tumours present with a headache. Tumours cause the pressure within the skull to rise, which causes a morning headache and vomiting that gradually gets worse. Brain scans are only necessary when these or other features of a tumour such as weight loss, seizures or personality change are present.
Subarachnoid haemorrhage
A sudden severe headache, usually at the back of the head, may be caused by a bleed inside the brain called a subarachnoid haemorrhage. Many people with this say it's like being hit with a baseball bat. It is commonly caused by the rupture of an aneurysm at the base of the brain and needs urgent investigation and treatment.
Temporal arteritis
Headaches in people over 50 can be due to temporal arteritis. It often feels different to previous headaches and can be accompanied by a tender scalp or pain when chewing.
Temporal arteritis is caused by inflammation of the artery in the temple (hence "temporal") and can be treated with steroids. It is important to diagnose early as it can lead to blindness if untreated.
Meningitis
A headache with a high temperature, neck stiffness and/or a new rash may be due to meningitis. This needs hospital treatment as soon as possible.
Ref: guardian.co.uk
