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’).
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.
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 dedicated Stills disease website at www.stillsdisease.uk
Undifferentiated arthritis
This is where the arthritis does not fit neatly into any of the other categories.