Juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is a type of arthritis that affects children aged 16 and under. It causes inflammation in the joints.

• juvenile means it affects young people
• idiopathic means the exact cause is unknown
• arthritis means inflammation of the joints

Around 1,000 children in New Zealand are living with arthritis, and JIA is more common in girls than boys.

The exact cause of JIA is unknown.

Research suggests it may involve a combination of genetic factors and environmental triggers such as infection.

JIA is an autoimmune condition. This means the immune system becomes overactive and attacks healthy cells, particularly in the joints.

This can cause:

• swelling
• stiffness
• pain

If not treated, inflammation can damage the joint, cartilage and bone.

JIA is an umbrella term with several subtypes:

Oligoarthritis

• most common type (50–60%)
• often begins between ages 2–4
• affects four joints or fewer at first
• increased risk of eye inflammation

Polyarthritis

• affects five or more joints
• can begin at any age
• more common in girls

Enthesitis-related arthritis (ERA)

• inflammation where tendons attach to bone
• often affects hips, lower limbs and lower back
• more common in boys

Systemic JIA

• affects boys and girls equally
• associated with fever and rash
• may affect internal organs

Psoriatic arthritis

• associated with psoriasis
• may affect any number of joints

JIA can come and go, with periods of remission (no active disease) and flares (active symptoms). Symptoms may include:

• swollen, stiff and painful joints
• joints that are warm to the touch
• reduced movement (e.g. limping)
• muscle weakness
• difficulty with daily activities
• tiredness, poor sleep or reduced appetite
• fever or rash (in some types)

There is no single test for JIA. Diagnosis may take time while other conditions are ruled out. Diagnosis is based on:

• medical history
• physical examination
• laboratory tests

Tests may include:

• blood tests (e.g. ESR, CRP, RF, ANA)
• X-rays
• ultrasound or MRI scans
• joint fluid testing

If JIA is suspected, your GP will refer your child to a paediatrician and then to a paediatric rheumatologist.

Eye inflammation (uveitis)

Uveitis is inflammation inside the eye and can be associated with JIA.

It often has no symptoms until later stages, so regular eye checks are important.

There is no cure for JIA. Treatment aims to control inflammation and reduce symptoms so your child can live as normally as possible. Treatment may include:

Medications

• non-steroidal anti-inflammatory drugs (NSAIDs)
• corticosteroids
• disease-modifying anti-rheumatic drugs (DMARDs)
• biological DMARDs

Other support

• education about JIA
• exercise and stretching
• support returning to normal activities
• pain, sleep and fatigue management
• social and psychological support

With the right treatment, most children can lead active and normal lives.

Dealing with chronic pain, fatigue, or missing out on activities can lead to children feeling frustrated, sad, and lonely. Reaching out for support can make a big difference.

It's important to connect with other tamariki who understand what it’s like to live with arthritis. To facilitate connecting with peers, we run a number of events and camps designed specifically for young people with arthritis and their whānau. These include:

• Teens Camp: – a weekend camp for youth aged 13 to 18 living with arthritis. It’s a chance to connect with others who are going through similar experiences, participate in fun activities, learn more about managing arthritis, and build confidence in a supportive environment
• Families Camp: – a weekend camp that brings families from around New Zealand together to connect, share stories, and access information and support, while children take part in ability-appropriate activities alongside peers who understand what they’re going through
• Day camps and local events: held throughout the year in different regions, these offer shorter, accessible opportunities for connection, learning, and support closer to home.

These programmes are about more than just arthritis - they're about building community and resilience, and making sure young people with arthritis feel seen, supported, and empowered.