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Juvenile Idiopathic Arthritis

Written by Ada’s Medical Knowledge Team

Updated on

What is juvenile idiopathic arthritis?

Juvenile idiopathic arthritis (JIA), previously known as juvenile rheumatoid arthritis (JRA) or juvenile chronic arthritis, is a chronic inflammatory condition primarily affecting the joints. It occurs in children under 16 years old.

Learn about types of arthritis occuring in adults here.

There are different types of JIA with varying symptoms and degrees of likelihood that a child will grow out of the condition. All types of JIA involve pain, swelling and stiffness of one or more joints.

JIA is an autoimmune reaction. This means that the immune system forms antibodies – proteins which ordinarily are meant to fight infections – that, in these cases, attack the body tissue. The causes are not well understood, but factors such as genetics and infections may influence the development of JIA.

Treatment often involves taking medications that suppress the immune system to a degree. Many children with the condition live well with treatment, and find that their symptoms improve over time. Many cases of JIA will resolve, though it is not possible to accurately predict this. In about 30 percent of cases, JIA can remain active into adult life. 1

JIA is the most common autoimmune joint condition in children. It tends to affect children younger than 10 but does not generally affect those younger than 6 months old. Girls are more commonly affected than boys and tend to show symptoms at a younger age.


Juvenile idiopathic arthritis (JIA) is characterized by joint inflammation over a period of six weeks or more.

Symptoms of inflammation in the joints include: 2 3

  • Swelling
  • Stiffness
  • Pain
  • Sensation of heat
  • Redness

Symptoms may develop slowly or abruptly, often with increased stiffness in the morning or following inactivity.

Less common signs and symptoms of JIA may include: 2 3

  • Rash on the torso, arms or legs, which quickly fades or changes
  • Fever, often spiking once or twice each day at about the same time
  • Anemia
  • Limping
  • Not using or a reluctance to use a certain limb
  • Loss of motor skill function
  • General pain
  • Fatigue
  • Sleep problems
  • Swollen lymph nodes
  • Weight loss and a reduced appetite
  • Psoriasis or other skin abnormalities
  • Uveitis – inflammation of the eyes
  • Growth disturbances leading to limb length discrepancy

The joints that are most commonly affected in JIA are the wrists, knees and ankles, but other joints can also be involved, such as the knuckles of the fingers.

Wondering whether you or a child in your care may be experiencing juvenile idiopathic arthritis? Try the Ada app for a free symptom assessment.

Types of juvenile idiopathic arthritis

There are six defined types of JIA, with diagnostic criteria varying according to certain factors, which include: 1 2

  • Number of joints affected in the first six months
  • Presence of laboratory markers in the blood that are typical of autoimmune diseases
  • Symptoms present in other areas of the body

In about 1 to 10 percent of cases of JIA, the arthritis may not fit into any of the types listed below, in which case it is called undifferentiated arthritis.

JIA may be classified as one of the following six subtypes:

Oligoarticular JIA: Formerly known as pauciarticular JRA or pauciarthritis, this is the most common type of JIA, making up about half of all cases. Diagnosis may be made if between one and four joints are affected in the first six months. This type of JIA is the most likely to resolve, leaving little or no joint damage. The condition is known as persistent oligoarthritis if it continues affecting up to four joints after six months, or known as extended oligoarthritis if it affects more than six joints after six months. Oligoarticular JIA commonly affects one or both knees and is often mild. It is also the type of JIA most likely to cause uveitis – eye inflammation – so requires regular eye checks.

Polyarticular JIA: rheumatoid factor negative: This accounts for about a quarter of all cases of JIA. Diagnosis of polyarthritis may be made if five or more joints are affected in the first six months. Rheumatoid factor-negative polyarticular JIA is diagnosed if a blood test for rheumatoid factor (RF) is also negative. It may involve tiredness and occasional, slight fever. This type of JIA may remain into adult life, but can go into remission, where the condition is symptomless. However, there is a remaining high risk of physical impairments.

Polyarticular JIA: rheumatoid factor positive: This accounts for about 5 percent of all cases of JIA. Diagnosis may be made if five or more joints are affected in the first six months and a blood test for rheumatoid factor (RF) is positive. It may involve tiredness and occasional, slight fever. This type of JIA may remain into adult life, but can go into remission, where the condition is symptomless. It tends to persist and has an increased risk of rapid progressive destruction of affected joints.

Systemic onset JIA, also known as Still’s disease or systemic juvenile idiopathic arthritis: This accounts for about 5 to 10 percent of all cases of JIA. Diagnosis may be made if there is arthritis in one or more joints with, or preceded by, fever of at least two weeks' duration, and if one or more of the following signs and symptoms are present:

  • Swollen glands in neck, armpits and groin
  • Quickly fading rash
  • Increased liver and/or spleen size
  • Pericarditis:: inflammation of the heart lining; pleuritis: inflammation of the lungs; or peritonitis: inflammation of the abdomen

There may be no joint symptoms in the first few weeks. The outlook for systemic juvenile idiopathic arthritis may be difficult to predict. Any fever or rash usually settles, and arthritis may continue for several years before settling.

Juvenile psoriatic arthritis: This accounts for about 2 to 15 percent of all cases of JIA. Diagnosis may be made if arthritis occurs with psoriasis, a skin condition that causes red, flaky, crusty patches of skin with silvery scales, or if arthritis occurs with at least two of the following factors:

  • Inflammation of toe or finger
  • Indentation on the nails
  • Painless separation of the nail from the nail bed
  • A first-degree relative with psoriasis

The outlook for juvenile psoriatic arthritis may be difficult to predict. In about 30 to 40 percent of cases, the condition remains into adulthood. This type of JIA usually has a mild course of disease.

Enthesitis-related arthritis: This accounts for about 2 to 10 percent of all cases of JIA. Diagnosis may be made if arthritis occurs with enthesitis – inflammation of the enthesis, the connective tissue between tendons or ligaments and bone – or if arthritis occurs with two or more of the following factors:

  • Pain in lower back
  • Positive HLA-B27 test: a marker of certain conditions
  • Other HLA-B27-associated conditions present, such as ankylosing spondylitis: spine inflammation; uveitis: inflammation of the eye; or ulcerative colitis: inflammation of the large intestine
  • Family history of HLA-B27-associated conditions
  • Child is male and older than six years

This type of JIA usually has a mild course of disease.


It is not completely understood what causes JIA; the definition of the term “idiopathic” is “of unknown cause”.

It is known that juvenile idiopathic arthritis is an autoimmune disease, which means that it is caused by abnormal functioning of the immune system. In a normally-functioning immune system, the body attacks foreign bacteria and viruses. In the case of autoimmune disease, the body accidentally attacks its own healthy tissue. In JIA, the body attacks its joint tissue.

Children with JIA produce an excess of white blood cells in the synovial membrane, the tissue that lines the cavities of joints; this causes inflammation. Occasionally, inflammation can also occur in other associated parts of the body, such as the lungs, heart and eyes.

Risk factors

There are three main risk factors for JIA: 4 5

Children aged 2 to 3 years old have the highest risk of JIA. It rarely occurs in babies younger than six months.

Generally, girls are more than twice as likely as boys to develop JIA, but this may vary depending on the particular subtype.

Genetic factors are involved in the risk of developing JIA. However, JIA is not solely genetic and is thought to be caused by a combination of genetic and other factors from the environment, such as infection, though thus far research has been limited in this area.


Diagnosis of JIA is generally made after referral to a pediatric rheumatologist, a type of doctor specializing in inflammation and pain in the joints, muscles or fibrous tissues of children.

To be classified as JIA, the signs and symptoms of the condition must occur before the age of 16 and persist for a minimum of six weeks. 1

There is no specific test for JIA. A pediatric rheumatologist will gather information to rule out other conditions and home in on the cause of the patient’s symptoms. Initially, diagnosis will be attempted from reported medical history, symptoms and a physical examination. Where this does not yield a definite diagnosis, further laboratory tests and medical imaging may be used.

Good to know: Keeping a diary of symptoms may be helpful in making the diagnosis. Try the Ada app for a free symptom assessment.

Interview and physical exam

The purpose of a physical examination is to look for early signs and symptoms of JIA.

Although it is rare for two or more members of the same family to be diagnosed with JIA, it is still important for doctors to look at one’s family medical history for any signs of predisposition to the condition. Doctors will pay particular attention to whether any family members have experienced an autoimmune disorder of any kind, as this may increase the chances of JIA.

Laboratory tests

If a doctor suspects JIA, one or more blood tests may be ordered to confirm the diagnosis. Tests may include the following: 6 7

Antinuclear antibodies (ANAs), which are proteins that recognize parts of the body’s own cells as something the body needs to fight in an autoimmune reaction. These are sometimes found in children with JIA, as well as in other autoimmune diseases and in children with a family history of autoimmune diseases. ANAs are also found in some healthy children.

Complete blood count (CBC) and metabolic panel, which is a blood test used to look at all types of blood cells to determine how many there are and what they look like, in order to detect anything unusual and diagnose many medical conditions. Anemia – low levels of healthy red blood cells – is common in children with JIA. Lower levels of white blood cells may be a sign of JIA or other inflammatory conditions, or a reaction to certain medicines.

Inflammatory markers, including erythrocyte sedimentation rate (ESR or sed rate) and C-reactive protein (CRP) tests may be done as these may show whether there is inflammation and to what degree. However, these markers are not always present alongside inflammation.

HLA-B27, which is a protein on the surface of white blood cells; it is genetically inherited and has been linked with some types of JIA.

Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibodies, which are proteins that attack healthy tissues. These are occasionally found in children with JIA.

Good to know: If it is possible that symptoms may be caused by an infection within a joint, then fluid may be drawn out from the joint with a needle and sent for laboratory testing.

Read more about Blood Test Results »

Medical imaging

A doctor may also recommend an X-ray, ultrasound or magnetic resonance imaging (MRI) of the affected joint to help with diagnosis. 3 However, at an early stage of JIA, any characteristic damage caused by the condition may not yet be apparent.


The main aims of treatment for JIA are:

  • To prevent joint damage
  • To minimize pain and other symptoms, and maintain quality of life
  • To prevent the development of associated conditions, such as growth problems, osteoporosis, puberty delay and reduced vision


Medications to treat JIA are usually prescribed by a pediatric rheumatologist. There are four main types of JIA drugs that are used: 2

Nonsteroidal antiinflammatory drugs (NSAIDs), such as ibuprofen, offer pain relief and reduce minor inflammation.

Disease-modifying anti-rheumatic drugs (DMARDs) work by suppressing the overactive chemicals released by the immune system, which can damage nearby bones, tendons, ligaments and cartilage. These are usually administered by mouth.

Biological response modifiers work by targeting the immune system and modifying the molecules causing the inflammation. This type of medication is generally reserved for the treatment of those who have not responded to DMARDs. They are usually administered through injection.

Steroids quickly improve inflammation. It is important that steroids are used judiciously in children and are tapered as soon as possible. The younger the child, the more a clinician will try to avoid this substance group.

They may be used in several ways, including being:

Taken orally to improve inflammation symptoms when these are present in other parts of the body, such as the heart lining, lungs and abdomen. This is only done rarely because of the risk of side effects, such as osteoporosis and growth impairments.

Absorbed through eye drops in the case of eye inflammation.

Injected into affected joints.

Exercise and lifestyle changes

Children should be encouraged to participate in as much physical activity as possible.

Physiotherapy and occupational therapy programmes can be helpful in maintaining strong joints and increasing the child’s ability to do normal activities.

Other treatments and lifestyle changes may include: 7

  • Nutrition counseling
  • Regular eye exams to find and treat any eye inflammation early
  • Making sure to get enough sleep

Good to know: Children with JIA may experience emotional, behavioral and academic difficulties due to being unable to participate in all physical activities and time spent away from school for hospital appointments and admissions. Therefore, children with JIA and their families may need support for these areas.


There are several complications of JIA, which may or may not affect a child, depending on the type of JIA they have, how severe it is and how well-managed. Complications can affect various parts of the body, including bones, joints, muscles and eyes.

Complications may include: 9

Growth problems, which may include misshapen body parts, uneven limb lengths or slow growth overall, due to inflammation leading to abnormal bone formation or from steroids. Keeping JIA flare ups under control is the best way to avoid growth problems.

Osteoporosis – bone thinning and weakening – which makes bones likely to fracture, may occur due to not staying active, not getting enough calcium or as a result of steroid treatment. Staying active as well as taking calcium and vitamin D supplements can help prevent osteoporosis.

Joint contractures, in which muscles and tendons do not grow properly and become stuck in a bent position, having been kept in this position to avoid discomfort due to inflammation. Regular stretching and use of splints can reduce joint tightness.

Muscle weakness and muscle loss, caused by abstaining from physical activities due to stiffness and pain. Regular exercise as recommended by a physiotherapist can help prevent muscle problems such as these.

Eye problems, such as uveitis – eye inflammation; glaucoma – optic nerve damage due to pressure of the fluid inside the eye; or cataracts – a clouding of the lens. A child with JIA should receive regular checks from an eye doctor to monitor for any eye problems before they create further damage.

Inflammation of other parts of the body, such as pericarditis – inflammation of the heart membrane, pleuritis – inflammation of the lungs; and peritonitis – inflammation of the abdomen lining. Such complications can be treated with anti-inflammatory medication.

Other names used for juvenile idiopathic arthritis

  • Juvenile rheumatoid arthritis
  • Juvenile chronic arthritis
  • Juvenile arthritis (umbrella term, including other conditions)
  • Childhood arthritis (umbrella term, including other conditions)


Q: What is the juvenile idiopathic arthritis prognosis?
A: There is not one JIA, but several subtypes. Prognosis therefore depends on the particular subtype. Many children with this condition respond well to treatment and find that their symptoms improve over time. Many cases of JIA will resolve and leave a person without symptoms in adult life, though it is not possible to accurately predict this. In about 30 percent of cases, JIA may remain active into adult life. Some people may have joint damage, which can limit physical activities, and a few may require joint replacements, possibly later in adult life. Growth may be delayed, but can often resume with treatment, though some children may be physically smaller than average.

Q: Does juvenile idiopathic arthritis require surgery?
A: In most cases, surgery is not required, especially with recent advancements in medication. However, there are a few instances where surgery may be recommended. These include cases resulting in spinal deformity, spinal instability, nerve problems or severe damage to a joint. Surgical options include hip and knee replacements. This may be delayed until bones have finished growing to avoid certain complications. 10

Q: What is the difference between juvenile idiopathic arthritis and juvenile rheumatoid arthritis? Are they just different ways of saying the same thing?
A: Not exactly, though there is a lot of overlap. Juvenile rheumatoid arthritis (JRA) used to be the name used in the U.S. for a group of childhood arthritic conditions. In the late 1990s, juvenile rheumatoid arthritis, along with the European term juvenile chronic arthritis, was replaced with the term juvenile idiopathic arthritis (JIA). This incorporates all of what was called JRA in the past and also includes all other forms of idiopathic arthritis in childhood. Anyone who was diagnosed with JRA would normally today be diagnosed with JIA, but not all those diagnosed with JIA would have been diagnosed with JRA. 11

Q: Is juvenile idiopathic arthritis (JIA) the same as rheumatoid arthritis in adults? If JIA persists into adulthood, will it become rheumatoid arthritis?
A: No, JIA and rheumatoid arthritis are separate conditions which require different treatment and have different outcomes. A person who has JIA that persists into adulthood is considered to be an adult with a history of juvenile idiopathic arthritis. While the two diseases may have some similarities, they also have some key differences. Like rheumatoid arthritis, JIA is brought on by chronic inflammation that may cause disability if left untreated. However, JIA is not a single disease, but in fact several related conditions. A small number of children with JIA, actually have a condition indistinguishable from adult rheumatoid arthritis. Typically, this presents in post-pubescent girls, who are found to have high levels of rheumatoid factor antibodies with five or more joints affected, usually in a symmetrical arrangement. 12

Q: What is juvenile arthritis? Is it the same as juvenile idiopathic arthritis?
A: Also known as pediatric rheumatic disease, juvenile arthritis (JA) refers to all autoimmune childhood conditions of the joints, muscles and fibrous tissues. JA includes JIA, as well as other conditions, such as juvenile lupus (see systemic lupus erythematosus) and fibromyalgia. 13