Juvenile idiopathic arthritis (JIA)

Juvenile idiopathic arthritis (usually called JIA) is the most common form of arthritis in children. It is when there is swelling in the joints, due to the immune system mistakenly attacking the lining of the joint. This causes the joints to be sore with reduced movement. It affects about 15,000 children in the UK, which is roughly one child in an average sized secondary school.

The cause of arthritis is not known. Some children get better quickly with not much treatment needed, while other children may need to be treated for a longer period of time. Some children may also continue to have arthritis when they are adults. There are various types of JIA:

  • Oligoarticular arthritis – which affects less than five joints in the first six months.
    • After six months, if five or more are then affected it can then be called extended oligoarticular arthritis.
  • Polyarticular arthritis – which affects five or more joints in the first six months.
    • There are two types, rheumatoid factor positive or negative.
  • Psoriatic arthritis – where as well as arthritis, either the child or their parent also has psoriasis (a typically affecting the knees and elbows).
  • Enthesitis related arthritis – is where the tendons or lower spine may also be inflamed.
  • Systemic arthritis – where children may also have a fever and rash.

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