Polyarthritis

Polyarthritis is a type of juvenile idiopathic arthritis (JIA).

This type of JIA tends to cause painful swelling in fingers, toes, wrists, ankles, hips, knees, and the neck and jaw.
It may come on suddenly or can steadily involve more joints over a period of months.
You may feel unwell and tired and occasionally develop a slight fever.
The symptoms may continue into adult life but it can go into a state where all the symptoms disappear. This is called remission.
A blood test will show whether a marker called rheumatoid factor is present in your blood.