A campaign has been launched to raise awareness about the little-known condition cluster headache.

Every two years or so, Tom Nash's life becomes a living nightmare.

Over a period of about six weeks, the 29-year-old develops excruciatingly-painful headaches that can last for two or three days.

The pain generally affects an area around his eye and spreads down to the cheek and jaw.

It is often so severe it wakes him at night. He cannot work and becomes drained and withdrawn, until the pain recedes.

Ordinary painkillers have no effect, nor do migraine treatments. Mr Nash said: "The pain is absolutely agonising and completely debilitating. It starts off slowly but, as the weeks pass, it gets worse and worse until it reaches a peak and then begins to fade away.

"It starts as a dull feeling around the eye and temples, then slowly develops into severe pain.

"At one time, it was so bad could do nothing but roll around the floor in agony while my wife called the doctor.

"I have memories of when was about eight asking whether my eye could be knocked out because the area around it used to become so painful.

"It got worse as I got older and I was finally diagnosed about ten years ago. The assumption is it is either a migraine or a bad headache but it is much more."

The charity Organisation for Understanding of Cluster Headache (Ouch UK) says although there are about the same number of cluster headache sufferers in the UK as there are sufferers of MS, hardly anyone has heard of the condition and most people afflicted with it are struggling along, isolated with their pain.

Cluster headache is a neurological disease believed to affect less than 0.5 per cent of the population, with men more prone than women.

The pain is excruciating, affecting one side of the head and face. It is described by one leading neurologist as "the most severe pain that can be experienced".

Because cluster headache is so rare, it is not unusual for sufferers to be misdiagnosed for many years and incorrectly treated for such conditions as migraine, severe neuralgia, chronic sinusitis, ear infections, eye or dental problems.

The cause of cluster headache is not known and there is no cure. It can begin at any age and it is a lifelong condition.

Ouch's aim is to reach as many sufferers and healthcare professionals in the country as it can to educate them about the symptoms of cluster headache and let them know help, advice and support is available.

A spokesman said: "The word 'headache' is something of a misnomer. Sufferers do experience piercing or stabbing pains in the side of the head but the worst of the pain is concentrated in the eye on the affected side of the face, often radiating down into the cheek, ear, jaw and upper teeth.

"Symptoms include tearing, swelling/redness of the eye and drooping of the eyelid. It is quite unlike migraine as sufferers with cluster headache are unable to lie down or remain still during an attack. They pace and dance around from one foot to another or rock violently back and forth."

Profuse sweating and raised temperature often accompany the pain, as does either a runny or blocked nostril on the affected side. Not all sufferers will experience all of these symptoms, but they will experience an attack (or attacks) at about the same time each day.

Once diagnosed by a neurologist, there are a number of medications that can help.

There are two types of cluster headache: Episodic and chronic. Mr Nash suffers from the former.

As such, he can have a period of weeks, or months, of experiencing from one to six attacks every day, each lasting from 45 minutes to three hours.

The condition then goes in to remission with months, or even years, free from pain.

But a chronic sufferer can experience these painful attacks month after month, year after year (25 years or more is not uncommon).

Anxiety, depression, dejection and irritability are all side effects of the pain and lack of sleep.

Many sufferers lose their jobs, their homes and their families as a result of their condition.

To find out more, write to: Ouch UK, Norham House, Mountenoy Road, Moorgate, Rotherham S60 2AJ or visit the web site www.ouch-uk.org