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Disease Profile

Systemic onset juvenile idiopathic arthritis

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

1-9 / 100 000

US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Systemic juvenile idiopathic arthritis; Systemic onset juvenile rheumatoid arthritis; Still's disease (formerly);


Lung Diseases; Musculoskeletal Diseases


The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.

Orpha Number: 85414

Systemic-onset juvenile idiopathic arthritis is marked by the severity of the extra-articular manifestations (fever, cutaneous eruptions) and by an equal sex ratio.

It represents 10-11% of cases of juvenile idiopathic arthritis (JIA). The prevalence has been estimated at 1-10 in 30,000 children with an annual incidence of 1-20 in 900,000 children.

Clinical description
Onset usually occurs between 3 and 5 years of age. The clinical signs include fever with oscillating temperatures over a 24-hour period and peaks of over 39°C or more. These 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-, oligoor 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. There are no specific biological signs but the inflammatory disease is severe with a large increase on the level of ferritin and a decrease in the percentage of glycosylated ferritin.

The underlying mechanisms and triggering factors have not yet been identified, but the disease can be clearly distinguished from other forms of JIA. The disease may represent an autoimmune disorder rather than an autoinflammatory disease (as for periodic fever and CINCA/NOMID).

Diagnostic methods
The clinical triad of daily fever (lasting more than 2 weeks), arthritis and transient cutaneous eruptions is vital for diagnosis (criteria established at in 2001 at the last international meeting in Edmonton). In the absence of cutaneous eruptions, the presence of an adenopathy, hepatosplenomegaly or serous effusion also confirm the diagnosis. There is no specific biological sign. Exclusion criteria are the presence of systemic arthritis or psoriasis in the patient, or a family history of psoriasis in one of the parents or a first-degree relative, HLA B27-positivity in males with onset of arthritis after 6 years of age and detection of rheumatoid factor IgM in two test samples taken three months apart. Other exclusion criteria include: the presence of ankylosing spondylarthritis, enthesitis and arthritis, sacroiliitis with an inflammatory enteropathy or acute anterior uveitis in the patient or a family history of one of these conditions in a parent or first-degree relative.

Differential diagnosis
The differential diagnosis should include fever associated with infection, connective tissue disease (notably lupus), acute leukaemia and other autoinflammatory diseases.

Management and treatment
Management should be carried out at a specialised centre. High doses of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) constitute the first-line treatment. In cases refractory to treatment over a period of 2-6 weeks, high-dose corticotherapy should be used. Disease-modifying antirheumatic drugs (methotrexate and biotherapy) may be recommended in case of corticoresistance but their effectiveness varies. Other drug treatments (thalidomide, interlukin-1 receptor antagonists (anakinra) and monoclonal anti-interleukin-6 monoclonal antibody (MRA) therapy) are available or currently under investigation for corticoresistant patients. In certain cases, intraarticular injection may be proposed.

The disease resolves before adulthood in around half of patients. In the remaining cases, the arthritis persists, with or without fever and cutaneous eruption. Severe sequelae are present in 20% of cases and involve growth delay, bone and cartilage erosion with functional handicap, and a risk of osteopaenia.

Visit the Orphanet disease page for more resources.


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Joint pain
Autoimmune disease
Autoimmune disorder

[ more ]

Elevated C-reactive protein level
Elevated erythrocyte sedimentation rate
High ESR
Joint swelling
Juvenile rheumatoid arthritis
Skin rash
30%-79% of people have these symptoms
Swollen lymph nodes
5%-29% of people have these symptoms
Abdominal pain
Pain in stomach
Stomach pain

[ more ]

Anterior uveitis
Enlarged liver
Swelling or irritation of membrane around heart
Pleural effusion
Fluid around lungs
Increased spleen size


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Systemic onset juvenile idiopathic arthritis. This website is maintained by the National Library of Medicine.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Systemic onset juvenile idiopathic arthritis. Click on the link to view a sample search on this topic.