<unk>  <unk> , formerly known as<unk>  rheumatoid arthritis (JRA), is the most common form of persistent arthritis in children.<unk>  is sometimes referred to as<unk>  chronic arthritis (JCA), a term that is not precise as<unk>  does not encompass all forms of chronic childhood arthritis.
Arthritis is the inflammation of the synovium (the lining tissues) of a joint.<unk>  is a subset of arthritis seen in childhood, which may be transient and self-limited or chronic.  It differs significantly from arthritis commonly seen in adults (osteoarthritis, rheumatoid arthritis), and other types of arthritis that can present in childhood which are chronic conditions (e.g. psoriatic arthritis and ankylosing spondylitis).
Juvenile idiopathic arthritis
Reactive arthritis
Psoriatic arthritis
Rheumatoid arthritis
Relapsing polychondritis
Crystal arthritis
Polychondritis
Enteropathic arthropathy