What is Juvenile Idiopathic Arthritis?

Diagnosing JIA 

Types of JIA

Healthcare Team for JIA

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What is Juvenile Idiopathic Arthritis (JIA)?

Juvenile Idiopathic Arthritis, also known as JIA, is the name given to several forms of arthritis in children and teenagers.

Juvenile means the arthritis begins before the age of 16, idiopathic means the cause is not known and arthritis means one or more joints are inflamed – that is, swollen, painful, stiff and they may not have as much range of movement as other joints.

JIA is an auto-immune condition, where the immune system gets confused and attacks healthy joint tissue, causing inflammation.

JIA can sometimes be seen in conjunction with other autoimmune conditions and while it principally affects the joints, it may also affect other organs including the eyes.

Every year approximately 1 in 10,000 children in Ireland is diagnosed with JIA making it almost as common as childhood diabetes. It can begin at any age, although it is most common in younger children and while it can develop in both boys and girls, most types are more common in girls.

For the vast majority of these children, arthritis is not the same as in adults.

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Diagnosing JIA 

A formal diagnosis should always come from a specialist paediatric rheumatologist working within a multidisciplinary team. The diagnostic process, which is the first key step in determining a treatment plan, may include the following –

  • A full history of symptoms
  • Clinical examination
  • Blood tests
  • Ultrasound scan and/or x-ray

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Types of JIA

There are several types of arthritis grouped under the umbrella term JIA, however the symptoms can vary. Just because something happens to one child, doesn’t mean it will happen to every child. 

Oligoarticular Arthritis

  • Four or fewer joints affected in first six months
  • If arthritis develops in other joints after the first 6 months, it will then be called extended oligoarticular arthritis

Polyarticular arthritis

  • Five or more joints affected in first six months
  • Can be further categorised as rheumatoid factor negative or even less commonly rheumatoid factor positive

Enthesitis related arthritis

  • When arthritis is associated with inflammation in the area where tendons attach to the bone (Enthesitis)
  • The most typically affected areas are the heel, arch of the foot, hips and knees

Psoriatic Arthritis (PsA)

  • Can affect any joint but often involves the fingers and toes
  • There may have been a swollen, ‘sausage’ shaped toe in a young child, which got better on its own; known as dactylitis [dak-ti-li-tis]
  • Psoriasis is a scaly rash typically affecting the knees and elbows, PsA can often be diagnosed where there is no evidence of psoriasis in a child, but a family member has psoriasis

Systemic Onset JIA

  • This is diagnosed if your child has arthritis and a typical pattern of recurrent fever and rash

Undifferentiated Arthritis

  • This means that a child/teenager’s symptoms don’t fit neatly into any one of the other types of JIA 

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Healthcare team

A child/teenager’s healthcare team may include some or a number of the following people. This will be as appropriate for each child according to their treatment plan.

Consultant paediatric rheumatologist or adult rheumatologist who sees children

They will be responsible for making the diagnosis and giving details of the management plan

Paediatric specialist nurse (or adult specialist nurse)

A specialist nurse has a degree of specialist expertise, knowledge and skill in a particular area and works closely with the consultant. They are often the key regular contact with families affected by JIA, providing education and support


A physiotherapist provides expert therapy to help maximise a child or young person’s movement and help them control pain in their joints and muscles. The physiotherapist’s role is to facilitate activity and participation, and provide guidance on sports and activities.

Occupational therapist (OT)

An occupational therapist can help a child take a more active role in life through helping them in the areas of playing and learning. They will encourage participation in everyday tasks and facilitate changes needed to allow this to happen


An eye doctor who will have an expert knowledge of uveitis which is a condition that can be linked to JIA


An expert in foot health, they will treat a wide range of problems affecting the feet, ankles and lower legs


A psychologist helps people with a number of problems, including behaviour, thoughts and feelings.


A radiographer is trained to operate and use equipment that takes images of the inside of different parts of the body. This includes x-rays, CT scans, MRI scans, ultra-sound. 

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For more in depth information on Juvenile Idiopathic Arthritis, and information on eye care, managing flares, physical activity, nutrition, and transitioning to adult care, contact our Services Support Officer 01-6470202 or our Helpline on 0818252846 [email protected] 

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