Systemic Juvenile Idiopathic Arthritis

What is systemic juvenile idiopathic arthritis?

Systemic juvenile idiopathic arthritis (sJIA), also known as systemic-onset JIA (SoJIA) is a rare auto-inflammatory disease, accounting for only 10% to 15% of children who have juvenile idiopathic arthritis (JIA). Though sJIA is considered to be a subtype of JIA, the symptoms, underlying cause and treatments for it are all different. Systemic JIA most commonly affects young children, but the symptoms may start at any age.

Is Still’s disease the same as systemic juvenile idiopathic arthritis?

Systemic JIA used to be called “Still’s disease,” though most pediatric rheumatologists now refer to this condition as SJIA or SoJIA. The adult form of sJIA is still known as adult-onset Still's disease (AOSD), and this is also a very rare disorder.

What are the symptoms of systemic juvenile idiopathic arthritis?

Children with sJIA have fevers, rashes and arthritis. These symptoms may occur all at once or spread out over several days or weeks:

• Arthritis symptoms can include swelling, warmth and pain in the joints, as well as stiffness and difficulty walking.
• Fevers typically occur once daily around the same time every day. This can make the disease hard to diagnose, as children may look very ill when they have the fever, but then normal once the fever goes away.
• The rash associated with sJIA is flat and pink in color, and it may be visible only when the fever is present. Sometimes, pressing on or lightly scratching the skin may cause the rash to appear.
• Other symptoms may include swollen lymph nodes and inflammation of internal organs such as the liver, spleen, the lining of the heart (pericarditis) or lung (pleurisy). Some children with sJIA go on to develop serious lung disease that leads to difficulty breathing.

What causes systemic juvenile idiopathic arthritis?

In children with sJIA, the innate immune system (the part of the immune system you are born with) is overactive. This leads to inflammation in the joints and in other parts of the body. The cause of this overactivity is not fully understood but is probably due to a combination of genetic and environmental factors.

How is systemic juvenile idiopathic arthritis diagnosed?

There are no specific medical tests for sJIA. A doctor will typically make a diagnosis based on:

• The collection of symptoms your child has.
• Physical exam findings.
• Laboratory tests (blood work usually shows signs of inflammation and helps to rule out an infectious cause).
• Imaging of the heart or lungs (echocardiogram, chest X-ray, chest CT scan).
• Skin biopsy (this is only performed in rare cases when the diagnosis is unclear).

Your child’s rheumatologist may recommend an exam by an ophthalmologist to evaluate for ocular inflammation (uveitis), although this is less common than in the other types of JIA.

How is systemic juvenile idiopathic arthritis treated?

There is no cure for sJIA. The goal of treatment is to reduce the symptoms and treat the underlying inflammation. Many children require corticosteroids, as well as other immunosuppressive medications. Biologic medications that target specific inflammatory molecules (interleukins), such as anakinra, canakinumab and tocilizumab, may help treat both the systemic inflammation and the arthritis. These medications are given by injection or IV infusion.

Updated: 11/16/2023

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