Juvenile Idiopathic Arthritis (JIA) is the onset of arthritis before the age of 16 years.  Idiopathic means that there is no known cause for the onset of the arthritis.  JIA can affect one joint or many, can last for a few months, or many years and beyond. Like Rheumatoid Arthritis, JIA is an autoimmune condition. This means that your body’s own immune system has started to malfunction and is starting to attack YOU, for example at your joints. Your immune system is designed to defend your body against infection. It should not attack your body. Sometimes the immune system becomes too active, and mistakenly attacks your body, and this is called ‘autoimmune’ disease.

What are the symptoms?

The most common symptoms of JIA are pain, stiffness and swelling of one or many joints.  Some children experience an unexplained intermittent fever and/or rash.  These symptoms are usually persistent, lasting more than 6 weeks.  Some children develop more widespread symptoms that can effect other areas of the body such as the eyes, liver and spleen.  This is called Systemic JIA.

Who is affected?

Juvenile idiopathic arthritis is a relatively rare disease, with an estimated incidence in the UK of 1 per 10,000 children per year, equivalent to 1000 children diagnosed per year.  Approximately 10% of children diagnosed with juvenile idiopathic arthritis have systemic juvenile idiopathic arthritis.  Some forms of juvenile idiopathic arthritis appear to be more common in girls.

Why does it happen?

The cause of juvenile idiopathic arthritis isn’t clearly understood, but may be linked to genetic and environmental factors.  It is possible that JIA can run in families, or can be triggered by certain things.

Have I or a child got JIA?

Some of the following symptoms may be intermittent, some continuous.

  • Swollen, stiff, and painful joints in the knees, hands, feet, ankles, shoulders, elbows, or other joints, often in the morning or after a nap
  • Eye inflammation
  • Warmth and redness in a joint
  • Less ability to use one or more joints
  • Fatigue
  • Decreased appetite, poor weight gain, and slow growth
  • High fever and rash (in systemic JIA)
  • Swollen lymph nodes (in systemic JIA)

These symptoms do not necessarily mean you or a child has JIA.  If you are at all concerned, you should make an appointment with the GP.

For more general information and support on JIA you may find these sites helpful:

JIA at National Rheumatoid Arthritis Society website


Children’s Chronic Arthritis Association website