By DANIEL ELKAN

Last updated at 20:03 18 September 2007

The symptoms sound like something from The X Files - sufferers complain of a crawling sensation all over the body, egg-like lumps under the skin and, even more bizarrely, cuts which produce tiny red and blue fibres.

Many doctors, however, are highly sceptical - dismissing the symptoms as imaginary and patients as delusional.

But a growing number of experts believe the symptoms are genuine, and the U.S. government's Centre for Disease Control and Prevention (CDC) is investigating the condition - Morgellons disease - as reported in the New Scientist.

Scroll down for more...

This belated recognition comes as a great relief to the many thousands of sufferers, such as Beverley Warren, who have struggled for years with this debilitating condition.

"It feels like tiny insects crawling or biting under my skin," says Beverley, 63, from Manchester.

As a result she hardly sleeps at night, constantly woken by the intense itching on her arms.

"I scratch and scratch, but it doesn't help. I've suffered hundreds of nights like this. Sometimes I just lie awake, crying."

Beverley's arms are covered with dozens of sores. Some have tiny, white, egg-like lumps on them, just under the skin surface.

More bizarrely, when Beverley scratches her arms, small black specks, which look like tiny grains of pepper, appear from under the surface of the skin.

The problem appeared 11 years ago.

Doctors and dermatologists have been unable to give her a diagnosis, and two skin biopsies have provided no answer.

At the suggestion of a dermatologist, Beverley applies creams to try to soothe the itching and then bandages her arms for two days to protect the area.

Unfortunately, this hasn't helped.

"The only thing that provides relief is when I put ice on my arms," she says.

Scroll down for more...

Then in April, Beverley discovered that she was not the only person with the problem.

After typing 'itching on the arms' into an internet search engine, she came across a website for Morgellons disease.

"My husband looked at the screen and said: 'My God, those are all the symptoms you've described.'"

Incredibly, more than 10,000 people worldwide had registered on the website claiming they suffered, too.

But in addition to Beverley's symptoms, many complained of something even stranger: tiny fibres, of various colours, growing out of their skin.

One of them is Rita, who lives in Somerset.

She says: "The fibres are 1mm or 2mm long and are either pinky red, blue, brown, black or transparent. They look like little hairs and most grow out of the lesions on my arms, legs and torso."

Four years ago, Rita, 47, started being affected by what many sufferers describe as brain fog.

"My thinking became cloudy and forgetful," she explains. "I jumble up my words and sometimes, if someone is talking to me, I can't understand what they are saying so I have to ask them to repeat themselves."

The condition forced Rita to give up her career as a legal secretary.

"The doctors are very dismissive. One doctor sent the fibres off to a lab, but all she said was that nothing abnormal had been detected."

Among Morgellons sufferers, this is a common experience.

The disease was named in 2002 by an American mother, Mary Leitao, whose two-year- old son one day pointed to his lip and said 'bugs'.

Mary was alarmed to find fibres growing there, but soon became frustrated that no doctor would investigate her son's condition.

She began researching it for herself, and came across a 17th-century article which described a condition, 'The Morgellons', where unusual hairs would grow out of the skin.

In the U.S., where the majority of cases are found, the number of people claiming to have the same symptoms - and the absence of a medical explanation - led to last month's launch of the government's CDC investigation, involving a team of specialists in epidemiology, environmental health, dermatology, chronic diseases, infectious diseases, pathology and mental health.

However, most experts believe the condition is a psychological disorder called delusional parasitosis.

Sufferers convince themselves the crawling sensations and fibres are evidence of an infection by a parasite.

"The brain tells them something is crawling on or under their skin," says

Professor Lynn Kimsey, an expert on insects and disease at the University of California.

"The human brain is wired to make connections between events, but we don't always draw the right conclusions. Only in a small proportion of cases do real parasites - such as mites - cause this type of thing."

Instead, Prof Kimsey says, the skin sensations are likely to be the result of changes in brain and nerve chemistry, commonly triggered by drug or alcohol abuse or hormonal changes such as the menopause.

The patients constantly scratch their skin - a process called neurotic excoriation - creating sores that never get the chance to heal.

As Professor Noah Scheinfeld, a dermatologist at Columbia University in the U.S., explains: "The skin becomes a sink for nervous energy and the slightest sensation can lead people to itch."

Even the fibres have a simple explanation: "They inevitably turn out to be lint from clothes, household fibres or hair," Kimsey says.

"Sores and scabs attract and trap these fibres."

The sceptics say Morgellons is best treated with dermatological creams for the sores - and possibly anti-psychotic drugs in severe cases.

But a handful of experts have found evidence that seems to contradict conventional explanations.

Randy Wymore, assistant professor of pharmacology at Oklahoma State University, stumbled across the Morgellons website and, surprised by the number of people claiming to be affected, offered to test some of the fibres at his lab.

"I thought it would be easy to determine their origin," he says.

But contrary to his expectations, the fibres did not match any common environmental ones.

So Wymore invited some Morgellons patients in to be examined by a colleague, Rhonda Casey.

She found that even under unbroken skin there were masses of fibres. A

fter extensive tests, scientists including a police forensics team drew a blank as to their origin, despite comparing them to more than 90,000 organic compounds.

Meanwhile, at the State University of New York, Vitaly Citovsky, professor of biochemistry and cell biology, found that the lesions of Morgellons patients test positively for the presence of agrobacterium, a bacterium used in the commercial production of genetically modified food - but not normally found in skin sores.

Psychiatrist Robert Bransfield has studied a database of 3,000 Morgellons patients and argues that the psychological profile of Morgellons patients does not fit with a diagnosis of delusional parasitosis.

"Before the onset of their illness, their mental status appears to be quite representative of the general population," says Bransfield.

"Later on they may become paranoid and delusional; but they don't start out that way."

Immunopsychology experts such as Bransfield are discovering that the body's own immune reaction to invasion by a parasite can significantly affect levels of brain chemicals, such as serotonin.

In other illnesses, such as hepatitis C, this can result in altered psychological states and mental symptoms.

Morgellons could work this way, too, Bransfield suggests.

Some test results have led researchers to speculate that Morgellons may be caused by an unusual fungal parasite.

For Beverley, the new investigation cannot come soon enough.

"I'm not delusional," she says. "I just want to find out what is happening to my body."