International League of Associations for Rheumatology classification of Juvenile Idiopathic Arthritis
Based on the International League of Associations for Rheumatology classification, what are the main types of Juvenile Idiopathic Arthritis? What percentage of JIA does each comprise?
JIA is an arthritis of unknown cause, beginning before the age of 16 years and lasting for at least 6 weeks. It affects 150 in 100,000 children. The subgroups are:
• sJIA (5%–15% of all JIA)
• Oligoarthritis (50%–80%)
• Polyarthritis, RF-positive (3%)
• Polyarthritis, RF-negative (17%)
• Psoriatic arthritis (7%)
• ERA/juvenile spondyloarthropathy (JAS) (∼15%)
• Undifferentiated arthritis.