The hallmark symptoms of Juvenile Idiopathic Arthritis (JIA) are painful, swollen, stiff joints (eg, neck). Affected joints may feel warm to the touch. These symptoms are usually worse when the child gets up in the morning or after a period of inactivity—a nap, for example. Pain may limit mobility of the joints, but some children do not even complain of pain, and sometimes the swelling isn’t obvious. The joints (eg, spine’s facet joints) involved vary with the type of arthritis, but JIA usually involves the knees and the small joints in the hands and feet. You may notice your child limping, being hesitant in using an arm or a leg, or, in a younger child, having trouble with fine motor skills.

• Your child may be very tired and irritable and may not be as active as usual.
• He/she also may have a fever, lose weight, and/or have eye problems.

What are Flares and Remissions?
The symptoms of JIA fluctuate, with flares (when symptoms are active or worse) and remissions (when symptoms lessen or go away). Some children may have only one or two flares, and then the disease completely remits, and a few develop a more aggressive disease with frequent flares or that never goes away. Symptoms and joint involvement vary with the type of JIA.

Systemic Arthritis
Formerly known as systemic juvenile rheumatoid arthritis (JRA), juvenile idiopathic arthritis can affect the whole body (it’s systemic). Fevers up to 103° F (or even higher) precede or accompany the onset of joint symptoms (even by months or years), and can rise and fall during the day. Rash is typical but is not always present, swollen lymph nodes are common. In some children (less than 50%), other organs may be involved as well, such as the liver, lungs, and heart. The child may have anemia and/or a low white blood-cell count.

Oligoarthritis (Oligoarticular JIA)
Oligoarthritis, which affects about 50% of children with juvenile idiopathic arthritis, is more prevalent in girls than in boys. From 1 to 4 joints are affected during the first 6 months; in some cases, more joints are involved after 6 months (extended oligoarthritis). The larger joints (eg, knees, ankles) are usually affected: it often begins with a swollen knee or ankle, which may not be painful, accompanied by morning stiffness. Children younger than 7 years at the time of onset are more likely to have a permanent remission later, but they are more likely to develop certain types of eye inflammation (iritis, or inflammation of the iris; or uveitis, inflammation of the area behind the iris). There are often no symptoms with iritis, so if your child has oligoarthritis, she will need to be monitored by an ophthalmologist to avoid the risk of vision loss.

Polyarthritis (Polyarticular JIA)
About 25% of patients have polyarthritis. At least 5 joints are involved during the first 6 months. Polyarthritis tends to involve the small joints (eg, fingers, wrists), although the weight-bearing joints can be affected. Polyarthritis is classified into 2 subtypes: seropositive (a high level of rheumatoid factor, a group of antibodies that accumulate in the joint lining, in their blood), and seronegative (no elevated levels of rheumatoid factor). There is no difference in symptoms.

Psoriatic JIA
Children with psoriatic JIA have both arthritis and either psoriasis or a parent or sibling with psoriasis, along with nail involvement and sausage-like swelling of a finger or toe. Psoriasis is a skin disorder that causes dry and scaly skin in one or more places.

Enthesitis-related JIA
Enthesitis-related JIA is actually a group of conditions. These include spondyloarthropathy (inflammation of the joints of the spine), which affects the soft tissues around the joints (entheses, which include ligaments, tendons, and joint capsules). Spondyloarthropathy typically affects the sacroiliac joints, which are located at the base of the back, as well as the knee and the Achilles tendon. A child with this type of arthritis may complain of back pain and stiffness, but the joint swelling may not be evident. He may also develop uveitis. Children with a certain genetic marker are more prone to enthesitis-related arthritis.

• View an animation about the body's sacroiliac joints.

Undifferentiated JIA
Children with this classification of JIA may have overlapping symptoms of 2 or more types, or their symptoms may not be typical of any one type. Symptoms and signs will vary.