What is Juvenile Arthritis?
Juvenile idiopathic arthritis (JIA) or juvenile arthritis (JA) is the name for a number of forms of arthritis in children and teenagers. Juvenile means that the arthritis began before you were 16 years old, idiopathic means that the cause is not known and arthritis means that one or more of your joints are inflamed – that is, they are swollen, painful, stiff and you may not be able to move them as far as normal. Even when you are over 16, doctors still use the term JA as this type of arthritis is different from adult forms of arthritis.
The term JA is relatively new and you may come across older terms, which mean essentially the same thing, such as juvenile chronic arthritis (JCA) and juvenile rheumatoid arthritis (JRA). The new term is now used by doctors worldwide to describe the different forms of arthritis in young people.
What causes JA?
The exact cause of JA is still not known. There is no clear evidence that it is inherited (runs in families) but there are certain genetic markers, which have been found more frequently in certain kinds of arthritis in children and adults. There is no evidence either that an infection causes JA. Sometimes children may have had a sore throat or other infection just before they become ill, but as yet no specific 'germs' have been identified.
We think that JA is due to a combination of inherited (genetic) factors and factors from the environment, for example an infection that has not yet been identified.
Are all joint pains due to JA?
No, not all joint pains are due to arthritis and not all forms of arthritis in young people are JA. Joint pains are common in young people and in most cases are short-lived (particularly after a viral illness) and cause no long-term problems. In fact, in children and young people, arthritis is an uncommon cause of joint pain.