Types of Juvenile Rheumatoid Arthritis
There are three forms of juvenile rheumatoid arthritis (JRA) -- they differ based on the number of joints they affect, the symptoms that they cause, and whether certain antibodies are present. For example, pauciarticular juvenile rheumatoid arthritis affects four or fewer joints and is the most common type of JRA. Polyarticular arthritis affects five or more joints. Of the three juvenile rheumatoid arthritis types, the systemic form of the disease is the least common. In addition to joint swelling, it is characterized by spiking fevers and a light skin rash.
Types of Juvenile Rheumatoid Arthritis: An Overview
Doctors classify cases of juvenile rheumatoid arthritis (JRA) into three types. These three types differ depending on:
- The number of joints involved
- The symptoms that occur
- The presence or absence of certain antibodies (special proteins made by the immune system) found by a blood test.
These classifications help the doctor determine how the disease will progress and whether the internal organs or skin is affected.
The three different juvenile rheumatoid arthritis types are:
Pauciarticular Juvenile Rheumatoid ArthritisPauciarticular (PAW-see-are-TICK-you-lar) juvenile rheumatoid arthritis is the most common form of JRA; about half of all children with JRA have this type of arthritis. In pauciarticular disease, four or fewer joints are affected. Pauciarticular disease typically affects large joints, such as the knees. Often, only one knee is affected. Girls under age 8 are most likely to develop this type of juvenile rheumatoid arthritis.
Some children have special kinds of antibodies in the blood. One is called antinuclear antibody (ANA) and one is called rheumatoid factor. Eye disease affects about 20 to 30 percent of children with pauciarticular juvenile rheumatoid arthritis. Up to 80 percent of those with eye disease also test positive for ANA, and the disease tends to develop at a particularly early age in these children.
Regular examinations by an ophthalmologist (a doctor who specializes in eye diseases) are necessary to prevent serious eye problems such as iritis (inflammation of the iris, the colored part of the eye) or uveitis (inflammation of the uvea, or the inner eye).
Some children with pauciarticular disease outgrow arthritis by adulthood, although eye problems can continue, and joint symptoms may recur in some people.