What is Juvenile Idiopathic Arthritis?
There are many terms used to describe a child with chronic arthritis. These include juvenile rheumatoid arthritis (JRA), juvenile chronic arthritis, and juvenile idiopathic arthritis (JIA). While JIA is used most by specialists in pediatric rheumatology, JRA is commonly used in the United States.
Several types of arthritis, all involving chronic (long-term) joint inflammation, fall under the JIA heading. This inflammation begins before patients reach the age of 16 years, and symptoms need to last from six weeks to three months to be called chronic. JIA may involve one or many joints, and cause other symptoms such as fevers, rash, and eye inflammation.
- Systemic-onset JIA affects about 10% of children with arthritis. It begins with repeating fevers that can be 103°F or higher, often accompanied by a salmon-colored rash that comes and goes. Systemic-onset JIA may cause inflammation of the internal organs as well as the joints, though joint swelling may not appear until months or even years after the fevers begin. Anemia (a low red blood-cell count) and elevated white blood-cell counts are also typical findings in blood tests ordered to evaluate the fevers and ongoing symptoms. Arthritis may persist even after the fevers and other symptoms have disappeared.
- Oligoarticular JIA, which involves fewer than five joints in its first stages, affects about half of all children with arthritis. Girls are more at risk than boys. Older children with oligoarticular JIA may develop “extended” arthritis that involves multiple joints and lasts into adulthood. Children who develop the oligoarticular form of JIA when they are younger than seven years old have the best chance of having their joint disease subside with time. They are, however, at increased risk of developing an inflammatory eye problem (iritis or uveitis). Eye inflammation may persist independently of the arthritis. Because iritis usually does not cause symptoms, regular exams by an ophthalmologist (eye doctor) are essential to detect these conditions and identify treatment to prevent vision loss.
- Polyarticular JIA affects five or more joints and can begin at any age. Children diagnosed with polyarticular JIA in their teens may actually have the adult form of rheumatoid arthritis at an earlier-than-usual age.
- With psoriatic arthritis, children have both arthritis and a skin disease called psoriasis or a family history of psoriasis in a parent or sibling. Typical signs of psoriatic arthritis include nail changes and widespread swelling of a toe or finger, called dactylitis.
- Enthesitis-related arthritis is a form of JIA that often involves attachments of ligaments as well as the spine. This form is sometimes called a spondylarthropathy. These children may have joint pain without obvious swelling and may complain of back pain and stiffness.