ICD-11

Juvenile idiopathic arthritis (JIA) is the term used to describe a group of inflammatory articular disorders of unknown cause that begin before the age of 16 and last over 6 weeks. Six disorders have been defined: systemic-onset juvenile idiopathic arthritis (formerly referred to as Still's disease), oligoarticular arthritis, rheumatoid factor-positive polyarthritis, rheumatoid factor-negative polyarthritis, enthesitis-related arthritis (spondyloarthropathies), and the juvenile form of psoriatic arthritis (see these terms). A seventh category has been defined comprising unclassified types of arthritis (types that do not correspond to any of the defined disease or that correspond to more than one of the disease definitions).

Arthritis in children, with onset before 16th birthday and lasting longer than 6 weeks

Systemic-onset juvenile idiopathic arthritis represents 10-11% of cases of juvenile idiopathic arthritis (JIA) and is marked by the severity of the extra-articular manifestations (fever, cutaneous eruptions) and by an equal sex ratio. Fever peaks are associated with transient cutaneous eruptions and diffuse erythematosis or urticarial-like lesions. The presence of arthritis is essential for diagnosis but may appear later in the disease course. The number of sites affected is variable (mono-, oligo- or polyarthritis) affecting both the small and large joints in a nearly symmetrical manner. This characteristic diagnostic triad may also be associated with an adenopathy and hepatosplenomegaly. Visceral complications (pericarditis, pleural effusion or serous peritonitis with abdominal pain) may be present.