Definition
Juvenile idiopathic arthritis (JIA) is the most common type of arthritis in kids and teens. It typically causes joint pain and inflammation in the hands, knees, ankles, elbows and/or wrists. However, it can also affect other body parts. JIA was previously called juvenile rheumatoid arthritis (JRA), but the name was changed because JIA is not a kid version of the adult disease. The term “juvenile arthritis” is used to describe all the joint conditions that affect kids and teens, including JIA.
Studies show that Black children with JIA were nearly twice as likely to have joint damage as their white counterparts.
Causes
The Arthritis Foundation states that JIA types are autoimmune or autoinflammatory diseases. That means the immune system, which is supposed to fight invaders like germs and viruses, gets confused and attacks the body’s cells and tissues. This causes the body to release inflammatory chemicals that attack the synovium (tissue lining around a joint). It produces fluid that cushions joints and helps them move smoothly. An inflamed synovium may make a joint feel painful or tender, look red or swollen or difficult to move.
The word “idiopathic” means unknown, and is symbolic of researchers not knowing why kids develop JIA. Despite the uncertainty, researchers believe that kids have certain genes that are activated by a virus, bacteria or other external factors. However, there is no evidence that foods, toxins, allergies or lack of vitamins cause the disease.
Symptoms
Children can start off with one type of JIA and develop symptoms of another type later.
The most common symptoms of JIA include:
- Joint pain or stiffness; may get worse after waking up or staying in one position too long.
- Red, swollen, tender or warm joints
- Feeling very tired or rundown (fatigue)
- Blurry vision or dry, gritty eyes
- Rash
- Appetite loss
- High fever
Symptoms that may be specific to the six types of JIA:
Oligoarthritis: Affects four or fewer joints, typically the large ones (knees, ankles, elbows). This is the most common subtype of JIA.
Polyarthritis: Affects five or more joints, often on both sides of the body (both knees, both wrists, etc.). Polyarthritis may affect large and small joints and affects about 25% of children with JIA.
Systemic: Affects the entire body (joints, skin and internal organs). Symptoms may include a high spiking fever (103°F or higher) that lasts at least two weeks and a rash. This subtype affects about 10% of children with JIA.
Psoriatic arthritis (PsA): Joint symptoms and a scaly rash behind the ears and/or on the eyelids, elbows, knees, belly button and scalp. Skin symptoms may occur before or after joint symptoms appear. PsA may affect one or more joints, often the wrists, knees, ankles, fingers or toes.
Enthesitis-related (spondyloarthritis): Affects where the muscles, ligaments or tendons attach to the bone (entheses). This subtype typically affects the hips, knees and feet, but may also affect the fingers, elbows, pelvis, chest, digestive tract (Crohn’s disease or ulcerative colitis) and lower back (ankylosing spondylitis). This type of arthritis is more common in boys and typically appears in children between the ages of eight and 15.
Undifferentiated: Undifferentiated means that your child’s symptoms may not match up perfectly with any of the