Juvenile idiopathic arthritis: an update.

Juvenile idiopathic arthritis (JIA) is the most common chronic arthropathy of childhood. Previous terminology identified this entity as juvenile rheumatoid arthritis. The 7 subsets of JIA identified under the new classification system are discussed, as are current treatments. A differential diagnosis of JIA is included as this condition continues to be diagnosed by exclusion. Recent studies, which discuss the outcome of adults with previous childhood arthritis, are reviewed.