About 300,000 children in America are affected by some form of juvenile arthritis or rheumatic disease. Joint inflammation and joint stiffness which persist for more than six weeks in a child age sixteen years old or younger is the initial criteria used to diagnose juvenile rheumatoid arthritis, more commonly referred to as JRA. There are three classifications for juvenile rheumatoid arthritis: pauciarticular, polyarticular, and systemic.

Pauciarticular JRA

Pauciarticular JRA affects four or fewer joints. About 50 percent of children with JRA have the pauciarticular type, making it the most common type of JRA. This type is further subdivided into early onset and late onset. Early onset affects more girls than boys by a 4:1 ratio. Typically, the children are very young, under five years of age. A common symptom associated with pauciarticular JRA is inflammation of the eye. Late onset is more common in boys, half of whom are positive for genetic marker HLA-B27. The large joints are commonly affected, and if there is eye inflammation it is usually not chronic.

Polyarticular JRA

Polyarticular JRA affects five or more joints and affects about 30 to 40 percent of children who have JRA. Girls are affected more often than boys by a 3:1 ratio. The small joints are more commonly affected, but large joints can also be affected. Two sub-groups of polyarticular JRA are determined by the presence or absence of rheumatoid factor. Most polyarticular JRA patients who are positive for rheumatoid factor are girls, age eight years old or older with symmetric arthritis affecting the small joints, who are also positive for HLA-DR4 (a genetic factor). They typically have a more severe course of the disease that resembles adult rheumatoid arthritis.

Systemic JRA

Systemic JRA, also referred to as Still's disease, equally affects boys and girls, with a usual age of onset between one and six years old. Approximately 10 percent of children with JRA have the systemic type. Fever and skin rash are distinguishing features. Internal organs may be affected. Usually the child is negative for rheumatoid factor and antinuclear antibodies.

Juvenile Arthritis — Naming Issues

It has been suggested that the term juvenile rheumatoid arthritis is confusing because it implies it's the same condition as adult rheumatoid arthritis, just with earlier onset. However, most children with arthritis do not have a form of disease that correlates with adult-onset rheumatoid arthritis. To make the distinction, some resources refer to childhood arthritis as juvenile chronic arthritis (JCA) or juvenile idiopathic arthritis (JIA). Still others suggest that simply juvenile arthritis (JA) is more accurate. Still, because old habits die hard, juvenile rheumatoid arthritis remains a commonly used terminology. It is important to remember that juvenile arthritis is not a single disease; it refers to a group of symptoms with many causes.

Young children may not complain of pain, so parents must be observant of signs that could be indicative of arthritis. Signs may include fatigue, lack of appetite, and lack of interest in playing or activities that would normally elicit a positive response. If the child is old enough to walk, the parent may also observe a subtle limp. A pediatrician or family doctor should be consulted. The signs and symptoms shouldn't be shrugged off as growing pains. If needed, a consultation with a pediatric rheumatologist may be ordered. Early diagnosis and treatment is very important so symptoms can be managed.