Juvenile chronic arthritis.

Juvenile Chronic Arthritis is a relatively uncommon childhood disease. There are no absolute diagnostic tests and many classification criteria have evolved (4, 15, 7) based variably on joint number, disease course, associated clinical features and rheumatoid factor seropositivity. These are of no help diagnostically, but do allow investigative and follow-up studies to compare like with like. It is generally accepted that there are three main modes of onset, the commonest being pauci-articular with less than five joints in the first 3 to 6 months. Arising from the population immediately around the old MRC rheumatism unit at the Canadian Red Cross Memorial Hospital, Taplow, this accounted for 68%, with a poly-articular onset in 20% and systemic onset in 12%. Despite this low incidence of systemic illness, it remains a great challenge.