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About Juvenile Arthritis (JA)

JA is an inflammatory, autoimmune disease that affects the joints and sometimes the eyes,  internal organs, and muscles, and is:

  • diagnosed in children from 0 to 16yrs of age
  • chronic ie continues for a long time.

The body’s immune system (its protective mechanism against infection) starts to mistakenly attack healthy cells of the body. This happens for reasons we don’t yet understand, possibly after being triggered by a virus or bacterial infection. The immune system fails to ‘turn off’ when the infection has been cleared producing ongoing joint inflammation called JA.

What are the types of JA?

1. Oligoarthritis

This is the most common type of JA, affecting 50-60% of children. It often begins in young children (under 5 years) and is more common in girls. Symptoms include: joint swelling and pain, with four joints or less affected. The child’s general health is not normally affected.

It usually affects large joints such as the knees and ankles, and typically does not affect the
same joints on both sides of the body. There is a risk of developing uveitis (inflammation of the eye).


2. Polyarticular

This type is divided into two groups, depending on whether the test for rheumatoid factor (RF) is negative or positive. Symptoms include:

  • Inflammation of many joints, affecting the same joints on each side of the
    body including fingers, toes, wrists, ankles, hips, knees, neck and jaw
  • Onset of symptoms may be sudden and typically the child feels unwell, tired, listless and may develop a slight fever
  • Affects between 20-30% of children with JA and is more common in girls

3. Systemic Onset JA

This is the least common type of JA. The early symptoms appear as a general illness involving:

  • Fevers that occur once or twice a day
  • Pink-coloured rash anywhere on the body, which comes and goes swollen glands in the armpits, neck and groin
  • Feeling tired with widespread aches and pains, although swollen joints may not appear for several weeks

4. Enthesitis-Related Arthritis (ERA)

Enthesitis refers to inflammation of the ligaments and tendons, which are attached to bones. may also be called juvenile spondylitis, juvenile spondylarthropathy, or seronegative-enthesopathyarthropathy syndrome.

ERA most commonly affects the spine, heel, hips, knees, and ankles is linked with an increased risk of acute uveitis, an inflammation of the eye that causes it to become red, painful and sensitive to light.


5. Psoriatic Arthritis (PsA)

The symptoms of psoriatic arthritis include joint pain in any number of joints. In addition this form of JA also involves the skin. This is usually seen as patches of scaly skin, called psoriasis. The skin symptoms can appear before or well after the joint symptoms develop, which may
mean your child is initially diagnosed with a different type of JA.