Juvenile arthritis is a term that encompasses a group of distinct diseases that affect children younger than 18, according to the Arthritis Foundation. Approximately 294,000 children currently have juvenile arthritis, which makes it one of the most common childhood diseases in the United States. The symptoms of juvenile arthritis are swelling and stiffness of the joints, and the complications include bone growth abnormalities.
Systemic Onset Juvenile Rheumatoid Arthritis (JRA)
Systemic onset juvenile rheumatoid arthritis, often abbreviated as systemic onset JRA, is associated with an acute illness causing high fevers that can last weeks or months, according to the Arthritis Foundation. Other symptoms associated with this form of arthritis are the appearance of red spots on the skin, usually on the thighs and chest. Systemic onset JRA generally affects the smaller joints in the hands, as well as the wrists, ankles and knees.
Polyarticular Juvenile Rheumatoid Arthritis (JRA)
Polyarticular JRA involves more than five, and often more than 20, joints in the body, according to the Merck Manuals. This form of juvenile arthritis tends to develop very slowly. The Arthritis Foundation adds that the most common joints affected are the knees, wrists and ankles. Furthermore, polyarticular JRA affects girls more commonly than boys, and often affects the same joint on either side of the body.
Pauciarticular Juvenile Rheumatoid Arthritis (JRA)
The Langone Medical Center of New York University reports that pauciarticular JRA affects both sexes equally, generally causing arthritis in boys under the age of 8 and girls under the age of 7. This form of JRA commonly affects the large joints, such as the knees, ankles, elbows and wrists. Only a joint on one side of the body is usually affected; thus, if the right ankle is affected, the left one usually is not. Pauciarticular JRA may also cause uveitis, an eye problem where a part of the eye becomes inflamed and irritated.
Juvenile Arthritis Caused by Other Diseases
The Arthritis Foundation reports that although rheumatoid arthritis is the most common form of arthritis affecting children, other diseases can also cause juvenile arthritis. These diseases include juvenile spondyloarthropies, which are a group of diseases that affect the spine and joints in the lower limbs; juvenile psoriatic arthritis, which is associated with psoriasis, a skin condition; juvenile dermatomyositis, a disease that also causes muscle weakness and a skin rash on the eyelids; and juvenile systemic lupus erythematosus, which is an autoimmune disease that causes skin rashes, kidney disease, and neurological problems, in addition to arthritis.
