What is JIA?

JIA is usually diagnosed by a specialist paediatric rheumatologist. This is a doctor who is trained in conditions like JIA. At the first assessment, the doctor will check each joint for inflammation and range of movement to see how many joints are affected. Each time you then return to the doctor, they will check the joints again to see how things have changed.

JIA does not only affect the joints. In around 1 in 5 children with JIA, the eyes can also be affected – a condition known as uveitis. If you are diagnosed with JIA, it is very important you get your eyes checked urgently for uveitis as it can lead to permanent sight loss if left untreated. More information about uveitis is available here and support is available from Olivia’s Vision. 

There are different types of JIA. Your doctor will tell you which type of JIA you have. You don’t need to know all about the different types, but you might find it helpful to know that there are different types – particularly when you meet other people with JIA. Each person with JIA is affected in a slightly different way. You are unique in every way, including your JIA.

Oligoarticular JIA

Also known as ‘oligo JIA’, this is the most common type of JIA. This is where 4 or fewer joints are affected in the first six months. In some children, it may spread to involve more joints (this is called ‘extended oligo JIA’).

Polyarticular JIA

Also known as ‘poly JIA’, this is where 5 or more joints are affected in the first six months.

Enthesitis-related arthritis

In this form of arthritis, usually called ERA, the inflammation is in the places where the tendons attach to the bone. Children with ERA often suffer pain in the spine and hips. 

Psoriatic arthritis

In this type of JIA, children have a skin rash called psoriasis, which looks like a dry scaly rash. They may also have changes to their nails, which looks like pitting.

Systemic JIA / Still's disease

Around 1 in 10 children with JIA have systemic JIA (sJIA, also known as Still's disease). Children with Still's disease usually have a non-contagious fever and rash. Inflammation not only affects the joints, but also other parts of the body including the heart, liver and lungs. Some children with Still's disease develop a rare but potentially life-threatening condition known as Macrophage Activation Syndrome. Still's disease is different to other types of JIA because it is considered ‘autoinflammatory’ rather than autoimmune. This means a different part of the immune defence is involved. Find out more about this subtype on our website at www.stillsdisease.uk 

Undifferentiated arthritis

This is where the arthritis does not fit neatly into any of the other categories.

Around 1 in every 1,600 children and young people under the age of 16 have JIA*. That is around 8,000 children in the UK alone.

At present, there is no cure for Juvenile Idiopathic Arthritis. All current treatments seek to reduce the symptoms of JIA, but are not a cure. Whilst these treatments have beneficial effects in reducing pain and inflammation, and provide some protection against long-term joint damage, they come with their own side-effects. In around half of all cases, children go into remission. But in the other half, they are confined to taking powerful drugs long-term, with all the side-effects and complications that can cause. 

If you are concerned that a child you know may have JIA, please see our #ThinkJIA resources at www.thinkjia.org 

Here at Juvenile Arthritis Research, our vision is a world where no child has to suffer from arthritis. Find out more about us and our aims. If you would like to support our work, click here. 

* "Around 1 in 1,600 children are diagnosed with JIA" is based on our latest research (https://doi.org/10.1093/rheumatology/kead700). The previous estimate of around 1 in 1,000 may continue to appear on our website and in some of our printed materials whilst we update to the new figures.