Overview of Juvenile Idiopathic Arthritis (JIA)
Like adults, children can develop arthritis. The most common type of chronic, or long-lasting, arthritis that affects children is called juvenile idiopathic arthritis (JIA). JIA broadly refers to several different chronic disorders involving inflammation of joints (arthritis), which can cause joint pain, swelling, warmth, stiffness, and loss of motion. The various forms of JIA have different features, such as the pattern of joints involved and inflammation of other parts of the body besides the joints. JIA may last a limited time, such as a few months or years, but in some cases it is a lifelong disease that requires treatment into adulthood.
JIA is “idiopathic,” meaning that its origins are not understood. While the exact causes of JIA are unknown, it begins when the immune system becomes overactive and creates inflammation.
With treatment, most children achieve periods of wellness (remission), and sometimes the disease goes away permanently with no further need for medications. It is important to see a doctor early if your child has swollen or stiff joints because delaying therapy can lead to joint damage, a lesser response to treatment, and other problems.
Who Gets Juvenile Idiopathic Arthritis (JIA)?
By definition, JIA begins in children and adolescents before the 16th birthday. Most types of the disease are more frequent in girls, but enthesitis-related JIA, a form of the disease that involves inflammation of the places where ligaments and tendons (flexible bands of tissue) attach to bones, is more common in boys. Systemic JIA, a rare type of JIA that features fever and rash, affects boys and girls equally. Children of all races and ethnic backgrounds can get the disease.
It is very rare for more than one member of a family to have JIA, but children with a family member with chronic arthritis, including JIA, are at a slightly increased risk of developing it. Having a family member with psoriasis is a risk factor for a form of JIA called psoriatic JIA.
Types of Juvenile Idiopathic Arthritis (JIA)
There are multiple types of JIA, each with distinct features. Generally, they all share arthritic symptoms of joint pain, swelling, warmth, and stiffness that last at least 6 weeks.
The types are:
- Oligoarticular juvenile idiopathic arthritis. This is the most common and mildest form, affecting four or fewer joints. It is considered persistent if symptoms continue for 6 months or longer, and extended if five or more joints become involved after 6 months of illness. Commonly affected joints are knees or ankles. A form of eye inflammation called chronic (long-lasting) uveitis can develop in children with this form of JIA. About half of children with JIA have this type.
- Polyarticular juvenile idiopathic arthritis–rheumatoid factor negative. This is the second most common type, affecting five or more joints in the first 6 months. Tests for rheumatoid factor are negative. The rheumatoid factor blood test checks for autoimmune disease, especially rheumatoid arthritis, which is an adult form of arthritis. Some of these children develop chronic uveitis.
- Polyarticular juvenile idiopathic arthritis–rheumatoid factor positive. A child with this type has arthritis in five or more joints during the first 6 months of the disease. Tests for rheumatoid factor, a marker for autoimmune disease, are positive. It tends to occur in preteen and teenage girls, and it appears to be essentially the same as adult rheumatoid arthritis.
- Enthesitis-related juvenile idiopathic arthritis. This form of JIA involves both arthritis and enthesitis. Enthesitis happens when inflammation occurs where a ligament or tendon attaches to a bone. The most common locations for enthesitis are the knees, heels, and bottoms of the feet. Arthritis is usually in the hips, knees, ankles, and feet, but the sacroiliac joints (at the base of the back) and spinal joints can also become inflamed. Some children get episodes of acute anterior uveitis, a sudden onset of inflammation of the front of the eye. Unlike most other forms of JIA, enthesitis-related JIA is more common in boys.
- Psoriatic juvenile idiopathic arthritis. Children with this type have psoriasis, a skin condition, as well as inflammation of the joints. The skin condition usually appears first, but sometimes painful, stiff joints are the first sign, with the skin disease occurring years layer. Pitted fingernails and dactylitis (swollen fingers or toes) are also signs of the disease.
- Systemic juvenile idiopathic arthritis. Systemic means the disease can affect the whole body, not just a specific organ or joint. Systemic JIA usually starts with fever and rash that come and go over the span of at least 2 weeks. In many cases, the joints become inflamed, but sometimes not until long after the fever goes away, and sometimes not at all if treatment is started quickly. In severe forms, inflammation can develop in and around organs, such as the spleen, lymph nodes, liver, and linings of the heart and lungs. Systemic JIA affects boys and girls with equal frequency.
- Undifferentiated arthritis. This category includes children who have symptoms that do not fit into any of the other types or that fit into more than one type.
Symptoms of Juvenile Idiopathic Arthritis (JIA)
Symptoms of JIA vary depending on the type, but all forms share persistent joint pain, swelling, warmth, and stiffness that are typically worse in the morning and after a nap or prolonged sitting. The pain may limit movement of the affected joint, although many children, especially younger ones, will not complain of pain. One of the earliest signs may be limping in the morning due to disease in one or both legs.
The symptoms of JIA may go through cycles, flaring for a few weeks or months followed by periods when they go into remission. Some children have just one or two flares and never have symptoms again, while others have many flares or symptoms that never fully go away.
Besides joint problems, the inflammation associated with JIA can cause other symptoms, such as:
- Eye inflammation. Uveitis (inflammation of the front and middle parts of the eye) often occurs in children with JIA. It usually starts within a few years after the JIA diagnosis, but in a small fraction of children, it appears before the joint symptoms or many years afterward. The type of JIA a child has may cause the development of different types of uveitis. Children with:
- Oligoarticular JIA, especially when it begins at an early age, can have chronic (long-lasting) uveitis that has mild or no symptoms. Children with polyarticular JIA without rheumatoid factor, or with psoriatic JIA are also at risk.
- Enthesitis-related JIA and some children with psoriatic JIA can have episodes of acute anterior uveitis, which has a sudden onset and causes eye pain, eye redness, and sensitivity to light.
If left untreated, uveitis can lead to eye problems such as cataracts, glaucoma, and vision loss, so it is important for children with JIA to have frequent eye exams.
- Skin changes. Depending on the type of JIA a child has, he or she may develop skin changes. Children with:
- Systemic JIA who have fevers can get a light red or pink rash that comes and goes.
- Psoriatic JIA can develop scaly red patches of skin. Psoriatic JIA can also cause pitted nails and dactylitis (swollen fingers or toes).
- Polyarticular JIA with rheumatoid factor can get small bumps or nodules on parts of the body that receive pressure, such as from sitting.
- Fever. Patients with systemic JIA typically have daily fevers when the disease begins or flares. The fever usually appears in the evening, and the rash may move from one part of the body to another, usually happening with the fever. Patients with other types of JIA do not generally develop fevers.
- Growth problems. Inflammation in children with any type of JIA can lead to growth problems. Depending on the severity of the disease and the joints involved, bones near inflamed joints may grow too quickly or too slowly. This can cause one leg or arm to be longer than the other, or can result in a small or misshapen chin. Overall growth also may be slowed if the disease is severe. Growth normally improves when inflammation is well-controlled through treatment.
Cause of Juvenile Idiopathic Arthritis (JIA)
In JIA, the body’s immune system—which normally helps to fight off infections and heal cuts and wounds—mistakenly attacks some of its own healthy cells and tissues. The result is inflammation, marked by pain, swelling, warmth, and stiffness. Inflammation from JIA can damage the joints, eyes, or other affected organs.
Scientists do not know why the immune system attacks healthy tissues in children with JIA, but they believe that a complex mix of genes and environmental factors are involved.
While the origin of the immune system’s overreaction in JIA is unknown, scientists have identified some of the molecules that contribute to inflammation in some forms of the disease. We now know that three molecules—TNF-alpha, IL-6, and IL-1—are involved in creating inflammation in the joints of many children with JIA. This has led to new therapies that specifically target these molecules.
Diagnosis of Juvenile Idiopathic Arthritis (JIA)
There is no single test that doctors can use to diagnose JIA. However, they may suspect that a child has the disease if he or she is younger than age 16 and has unexplained joint pain, stiffness, or swelling that has lasted for at least 6 weeks. Doctors usually diagnose JIA by ruling out other conditions that have similar features.
The process doctors use involves the following.
Medical History and Physical Exam
During the examination, the doctor usually:
- Asks about your child’s symptoms and when they began. They may also want to know about your child’s family medical history because autoimmune diseases like JIA can run in families.
- Checks your child’s joints and skin.
- Watches your child’s movements for signs of trouble walking, climbing onto the examination table, moving the neck, or raising or closing the hands.
- Shines a small light into your child’s eyes to look for eye problems that stem from uveitis (inflammation of the middle part of the eye), such as glaucoma or cataracts.
- Checks the lymph nodes and abdomen for signs of swelling or sensitivity.
The doctor may order blood tests for:
- Erythrocyte sedimentation rate (ESR or “sed rate”) and C-reactive protein (CRP). These blood tests are measures of inflammation, or so-called inflammatory markers. They are often high in children with systemic JIA, and may be elevated in children with other forms of JIA as well. But they are not specific for JIA and may also be elevated for an unrelated reason such as an infection. In cases where inflammatory markers are elevated because of JIA, doctors can use these tests to monitor if treatments are working.
- Autoantibodies. Antibodies are molecules made by the immune system—for example, in response to infections. Autoantibodies are antibodies that target one's own cells and tissues. Autoantibodies that may be found in children with JIA include:
- Antinuclear antibody (ANA). An autoantibody directed against substances in the cell nucleus, ANA is found in many children with JIA, but children without JIA may also test positive. Those who test positive for ANA are at higher risk of developing eye inflammation and need to follow up more frequently with an eye doctor.
- Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) antibodies. These autoantibodies are rarely detected in children with JIA. When present, they usually correspond to a diagnosis of rheumatoid factor-positive polyarticular JIA.
- HLA-B27. This gene is a risk factor for enthesitis-related JIA. However, some children who have enthesitis-related JIA test negative for HLA-B27, and not all those who test positive have, or will ever develop, the disease.
- Other lab tests. Doctors may also order a basic panel of tests, including liver and kidney function tests, as well as a complete blood count (CBC). The CBC can tell if your child has anemia (low levels of red blood cells), which can occur in people with systemic JIA or other chronic inflammatory disorders.
The doctor may order the following:
- X-rays, which use a small amount of radiation to assess the structure of bones. They are often the first type of imaging study the doctor orders because they help rule out other causes of joint pain, such as a fracture, infection, or a tumor. As JIA progresses, x-rays can show if there is damage to the joint.
- Ultrasounds, which rely on high-frequency sound waves and are a noninvasive way to visualize joints without using radiation. Unlike x-rays, they can detect fluid and inflammation, which typically occur before any damage can be seen on x-rays.
- Magnetic resonance imaging (MRI), which is a highly sensitive tool for visualizing the joints. MRIs use large magnets to create detailed, three-dimensional images of the joints, including inflammation, cartilage, and bone.
The diagnostic process will determine if your child has JIA, and if so, identify the type he or she has. It will also provide information to help doctors best treat the disease.
Treatment of Juvenile Idiopathic Arthritis (JIA)
The goals of treatment are to:
- Control inflammation.
- Reduce pain and stiffness.
- Prevent joint and organ damage.
- Preserve and improve joint function.
- Promote physical and psychosocial growth and development.
- Achieve remission (little or no disease activity or symptoms).
- Allow for full engagement with normal activities (e.g., school, work, sports, social life, family life).
Most children with JIA need a combination of medicines and a healthy lifestyle, including a balanced diet and exercise, to reach these goals. The specific treatment plan will depend on the child’s age, the type of JIA, and on other factors, such as disease severity. In general, doctors will treat the disease aggressively early on, tapering off medications once remission is reached.
The types of medications your child may be prescribed include:
- Anti-inflammatory and pain medications. These can help alleviate pain and swelling from inflammation. They are often prescribed by the doctor, but some are also available over the counter.
- Disease-modifying anti-rheumatic drugs (DMARDs). These oral medications suppress the immune system on a broad level, helping to prevent progression of the disease and saving the joints from permanent damage. Depending on the drug, they may be taken by mouth or given as injections under the skin. DMARDs are sometimes combined with biologic response modifiers.
- Biologic response modifiers. By blocking specific immune signals that cause inflammation, biologic response modifiers help to prevent progression of JIA, achieve remission, and protect against permanent damage. Depending on the drug, they may be given as injections under the skin or intravenously. These drugs are sometimes combined with oral DMARDs. If doctors prescribe drugs in this class, they are usually inhibitors of TNF-alpha, IL-1, or IL-6, molecules that are known to promote inflammation in JIA.
- Corticosteroids. When injected into an affected joint, these strong inflammation-fighting drugs usually bring fast relief, though it is not always long lasting. In certain situations, they are given by mouth or intravenously, especially for systemic JIA and occasionally to alleviate severe symptoms from other types of JIA. Because they are powerful drugs with many possible side effects, doctors typically prescribe the lowest dose of steroids necessary and taper off as quickly as possible.
Physical therapy can be an important part of JIA treatment. The doctor may recommend physical therapy to help:
- Relieve pain.
- Improve and maintain range of motion in affected joints.
- Strengthen muscles.
- Prevent injury from sports or other physical activities.
A physical therapist can also teach pain-reducing techniques and develop a home exercise program for your child.
Routine Monitoring and Ongoing Care
Regular medical care is important because your doctor can:
- Monitor how well treatment is working.
- Adjust the treatment as needed. If a medication is not working well or if there are side effects, the doctor may try a different dosage, a different medicine, or a combination of medicines. If the treatment is working very well and the disease is well controlled, the doctor may discuss options for tapering or stopping medicines.
Who Treats Juvenile Idiopathic Arthritis (JIA)?
Treating juvenile idiopathic arthritis typically requires a team approach that involves several different health care providers.
JIA is primarily treated by:
- Pediatric rheumatologists, who specialize in treating arthritis and other diseases in children that involve the joints, bones, muscles, and immune system.
Other members of your child’s health care team may include:
- Mental health professionals, who can help children cope with difficulties in the home and at school that may result from their medical condition.
- Occupational therapists, who teach ways to protect joints, minimize pain, perform activities of daily living, and conserve energy.
- Ophthalmologists, who diagnose and treat diseases of the eyes.
- Orthopaedists, who specialize in the treatment of and surgery for bone and joint diseases or injuries.
- Pediatricians, who provide routine medical care for children.
- Physical therapists, who help to improve joint function.
- Rheumatology nurses, who may serve as the main point of contact with your doctor’s office about appointments, tests, medications, and instructions.
- Social workers, who can help your child and your family deal with lifestyle changes caused by arthritis. A social worker can help you find resources and can serve as a liaison with your child’s school, working with school-based staff to address any issues.
Living With Juvenile Idiopathic Arthritis (JIA)
JIA affects the entire family; all family members must cope with the special challenges of the disease. Having JIA can strain your child’s participation in social and after-school activities and make schoolwork more difficult. Nevertheless, it is important to treat your child as normally as possible.
Certain activities can help improve children’s ability to function on their own and maintain a positive outlook. These include:
- Managing medical care. Ensure that your child receives appropriate medical care and that you and your child follow the doctor’s instructions. Learn as much as you can about the disease and its treatment. Many treatment options are available, and because JIA is different in each child, what works for one may not work for another. If the medications that the doctor prescribes do not relieve symptoms or if they cause unpleasant side effects, you and your child should discuss other choices with the doctor. It can be helpful to keep a day-to-day record of your child’s symptoms and side effects of medications. Being prepared for doctors’ appointments can help reduce the anxiety associated with them.
- Balance rest and exercise. Your child should have more rest when JIA is active and more exercise when it is not. Rest helps to decrease active joint inflammation, pain, and fatigue. In general, shorter rest breaks every now and then are more helpful than long times spent in bed. During symptom-free periods, many doctors encourage playing team sports and other physical activities, which help to maintain strong muscles, joint mobility, and flexibility, while providing social interactions with other children. Swimming is especially helpful because it uses many muscles and joints without stressing the joints. Exercise can also help:
- Improve sleep.
- Decrease pain.
- Keep a positive attitude.
- Maintain a healthy weight.
Talk to your child’s health care provider before beginning an exercise program.
- Care for the joints. Cold packs can help ease the swelling and numb painful joints, while heat treatments, such as hot showers or heating pads, work best for stiff joints and muscles. Wearing a splint (a piece of hard material, usually wrapped in fabric) for a short time around a painful joint can reduce pain and swelling. Talk to your child’s doctor or a physical or occupational therapist before using a splint.
- Partner with your child’s school. Help your child’s school to develop a suitable lesson plan, and educate your child’s teacher and classmates about JIA. Some children with severe forms of the disease may be absent from school for prolonged periods and need to have the teacher send assignments home. Some minor changes—such as having an extra set of books or leaving class a few minutes early to get to the next class on time—can be helpful. With proper attention, most children progress normally through school.
- Encourage a healthy diet. There is no evidence that a special diet helps to treat JIA, but a healthy, balanced diet is important for maintaining overall health.
- Help your child cope with stress. Young people with chronic conditions such as JIA are at greater risk of having emotional or mental health problems, such as anxiety or depression. Having a strong support network of friends and family in place can help a young person through difficult times. Ways to cope with stress can include:
- Doing relaxation, distraction, or visualization exercises.
- Being physically active.
- Seeking expert help from a mental health professional.
- Joining a support group for children with JIA.
Research Progress Related to Juvenile Idiopathic Arthritis (JIA)
The NIAMS supports translational and clinical research at universities and other organizations throughout the country that are studying JIA. Researchers at these research centers and at the NIH are continuing work to understand what causes the disease, which may help them identify new treatment strategies. An active area of investigation is the search for genetic factors that may underlie the various forms of the disease. Many efforts are also aimed at testing the effectiveness of biologic response modifiers, which target specific inflammatory pathways that have been implicated in JIA.
Following are some examples of other types of studies that are ongoing.
- Children with JIA must be screened frequently for uveitis (inflammation of the middle of the eye). To improve uveitis monitoring, researchers are developing a risk estimator tool based on genetic variations, biomarkers, demographics, and clinical factors. By helping to identify those at high risk, the tool will help doctors initiate treatment early on, reducing the chance of vision loss.
- The causes of JIA are not known, but disturbances of the microbiome (the collection of all the microbes that inhabit the human body) have been linked to other inflammatory diseases. Scientists are studying the potential impact of antibiotics, infections, and microbiome imbalances on the development and activity of JIA.
- Macrophage activation syndrome (MAS) is a rare, but dangerous, complication of systemic JIA. It involves uncontrolled activation of immune cells called macrophages and T-cells, which leads to an overwhelming inflammatory response. Investigators are studying the changes that occur to macrophages during MAS so that they can find new ways to prevent and treat it.
- With the current array of therapies available, many children with JIA achieve long-term remission. Research is underway to understand whether and how to taper patients off of their medications once the disease becomes inactive.
- HLA-B27 is a protein associated with enthesitis-related JIA and certain other inflammatory diseases. The protein has the tendency to misfold inside cells, which can trigger inflammation. By working to understand how cells respond to HLA-B27 misfolding, investigators hope to find ways to mitigate inflammation and possibly find new ways to treat the disease.
- In an effort to better understand the causes of JIA, researchers are conducting a trial in which they follow a set of patients with systemic JIA over time. Using information gathered from periodic health evaluations and laboratory tests, the investigators expect to learn more about the genes and environmental factors involved in the disease, which may lead to new diagnostics or therapeutic strategies.