By Jane Elliott
BBC News health reporter
Emma was diagnosed at the age of four
For seven years Emma Doree has been in almost constant pain because of a condition that many people think only affects the elderly.
Every joint in her body can hurt. Some days she is confined to bed - on others she is well enough to go to school.
The 11-year-old from near Middlesbrough has systemic juvenile idiopathic arthritis, and already much of her young life has been spent in hospital.
A national appeal hopes to raise more than £3m to help research the condition that has afflicted Emma and about 12,000 other children in the UK.
She says: "People aren't aware that you can have arthritis this young.
"They say 'are you being serious?' when you tell them.
"I think they are a bit shocked and they do not believe it. They say 'old people get it, you can't have it.'
"It is hard for me because my friends can go to the cinema and play out, but I can't. It is quite frustrating.
"I can't run around as much and do as much PE. If they are doing football I have to play badminton as there is less chance that I will fall over."
Her mother Sally said when Emma was first diagnosed, at the age of four, it came as a complete shock.
"I knew nothing about it. I am a school teacher and in 20 years of teaching I had not come across a child with it.
"It was the last thing I thought it was going to be."
The family first started noticing problems with Emma's walking around her fourth birthday.
"She said she had problems with her knees and we thought she had sprained her ankle. Then she had flu symptoms for about a week and a half.
"She was admitted to hospital with a stiff neck and a high temperature and rashes all over her body.
Noddy backing the appeal
"She was in hospital for a week. The rashes localised around her joints and they told us it was arthritis."
Over the last seven years Emma has been on heavy steroids, but now her condition is controlled with the new biological drugs and anti-inflammatory drugs, but she still suffers a lot of pain.
Her mother said: "You have flare-ups and periods of remission.
"When she is in a flare-up it is very difficult for her and frustrating as well. She can wake-up in the morning well, but be tired by lunchtime.
"She has regular physio and hydrotherapy. Unless she is poorly one of the worst things you can do is sit around. Doing something active can help keep her joints healthy.
What Causes Juvenile Idiopathic Arthritis?
The cause is unknown, but research indicates it is an autoimmune disease
In autoimmune diseases, white blood cells lose the ability to distinguish between the body's tissues and harmful invaders like bacteria and viruses
This leads to the release of chemicals that can damage healthy tissues and cause inflammation and pain
"We try to remain as positive as we can. You can't turn the clock back, but you can learn to live with it."
But Sally said the future is still unclear for children like Emma.
"In the majority of cases it would appear that they do grow out of it, or as they get older they learn to live with it.
"There is also a school of thought that they go into remission and that it can return in their 30s and 40s.
"If they knew what the outcome was they may be able to know how it started."
Pat Woo, an international expert in childhood arthritis and professor of paediatric rheumatology at London's Great Ormond Street Hospital, said more needed to be done to help children like Emma.
"People think only older people can get arthritis, but in fact teenagers, children and even babies can develop a painful and potentially very serious childhood forms of the disease that affects not just their joints but the whole of their body, and can have very serious consequences in terms of their growth and development."
Professor Woo is leading a major Arthritis Research Campaign-funded research programme studying the genetic background that predisposes children to develop different types of arthritis.
As a result of the research, a new drug - currently known as MRA (myeloma receptor antibody) - is now in development, which could put the disease into remission.
"Research has led to new treatments which can vastly improve children's quality of life, but we still don't have a cure, and so much more needs to be done," she added.
Professor Woo described the results of the drug trials involving a small group of children at Great Ormond Street Hospital as the best she had seen.
"The trial finished last year and the drug appeared to be very effective with no major side-effects.
"It needs to be developed further to check for safety and efficacy but this is a good start."
She added: "A new multi-centre clinical trial is expected to start shortly, with results within five years."
Enid Blyton, creator of the Noddy character, granted the Arthritis Research Campaign the rights to use the character for fundraising.
He is being used as the mascot for the current fund-raising campaign.