For some reason, the immune system goes into overdrive and starts to attack body tissues. In rheumatoid arthritis, the tissue that is attacked is joint tissue. There are different types of arthritis that occur in children that are distinct from adult types. General points about children with arthritis are that they have a better chance of outgrowing arthritis, have a much lower chance of disability, and many types of arthritis will show up in one or two joints only. There is overlap in the types.
Some children can get a form identical to adult rheumatoid arthritis.
In childhood arthritis, the most typical kind is called JRA - juvenile rheumatoid arthritis. It will occur around age four to five. Worrisome symptoms to watch for would be persistent symptoms, symptoms that last for several weeks. Those symptoms would include stiffness in the morning that is prolonged. Other symptoms would be persistent swelling of joints or persistent aching in joints.