Children who develop pain, swelling and stiffness of the joints may have a disease called arthritis. The most common subtype of arthritis in children is known as juvenile idiopathic arthritis. Approximately 300,000 children in the United States have arthritis, and juvenile idiopathic arthritis affects children as young as two years old.
Currently, scientists and doctors are unsure about what causes the development of juvenile idiopathic arthritis. Studies have failed to show any evidence that would point to an involvement of different types of food, allergies and vitamin deficiencies in the development of this disease. However, some studies have shown that there is an association between genetics and juvenile idiopathic arthritis. To date, research studies have revealed the involvement of several genetic markers, and are currently investigating the impact of hundreds more. However, it is thought that the presence of a genetic marker is not sufficient to cause the development of juvenile idiopathic arthritis. These differences in genetics can explain the different symptoms and levels of severity across individuals.
Juvenile idiopathic arthritis can be divided into six subgroups: systemic, oligoarticular, polyarticular, psoriatic, enthesitis-related and undifferentiated. While each subgroup has its own unique symptoms, the common signs and symptoms that are pervasive across all subgroups include:
- Joint or muscle pain, which is particularly severe after a day of activity or in the morning. This pain might be especially prominent in their knees, feet, jaw, hands or neck. The pain generally improves as the patient goes about their day. This type of muscle pain might not be respond to over-the-counter drugs such as acetaminophen and you may have to go to a doctor to get prescription pain killers.
- Pain that develops slowly and affects joints symmetrically (on both sides of the body).
- Joint stiffness, which is especially severe in the morning and improves with movement during the day. Joint stiffness can cause the child to not be able to perform normal everyday activities like opening the door.
- Joint swelling or inflammation
- Fever. The type of fever seen in children with juvenile idiopathic arthritis normally occurs alongside bouts of fatigue, and can occur quite frequently. One of the ways you can distinguish an arthritis-related fever as opposed to an infection-related fever is that an arthritis-related fever will not be accompanied by respiratory or stomach infections.
- Rashes on skin, particularly pink rashes that appear over knuckles, cheeks and nose. These types of rashes don’t usually itch or ooze out liquid, and they last for several days, maybe weeks.
- Weight loss. While weight fluctuations can happen frequently in children, if a child displays symptoms of weakness or fatigue, does not have an appetite, and is losing weight, then may have juvenile idiopathic arthritis.
- Uveitis (inflammation of the eye).
- Limping due to joint or muscle stiffness. In arthritic children who are especially young, they may not able to perform motor skills such as walking or holding objects, tasks they recently learned.
These are the signs and symptoms sorted by the different subtypes of juvenile idiopathic arthritis:
- Systemic juvenile idiopathic arthritis. This type of juvenile idiopathic arthritis is classified as an autoimmune disease, which means that it develops because our body’s immune system attacks its own tissue instead of just foreign pathogens such as bacteria and viruses. Systemic juvenile idiopathic arthritis affects about 10 percent of all children with juvenile idiopathic arthritis. The symptoms associated with the development of systemic juvenile idiopathic arthritis include:
- Inflammation in joints
- High fever that can last for two weeks or longer
- Skin rash
- Inflammation of heart, lungs or outer linings
- Anemia (low red blood cell count)
- Oligoarticular juvenile idiopathic arthritis. This type of arthritis demonstrates involvement of up to four joints and tends to affect large joints such as those in the knees, elbows or ankles. Patients with oligoarticular juvenile idiopathic arthritis are at a higher risk for uveitis.
- Polyarticular juvenile idiopathic arthritis. This type of arthritis involves five or more joints, and tends to affect the smaller joints of the body such as those of the fingers and hands. However, in some instances, larger joints such as knees can also be affected. This subtype affects up to 25 percent of all children with juvenile idiopathic arthritis.
- Juvenile psoriatic arthritis. This type of arthritis develops in people that have already have a pre-existing skin disease known as psoriasis. Generally, symptoms of psoriasis manifest several years before any symptoms of juvenile psoriatic arthritis. This subtype tends to involve inflammation of one joint or more and can frequently affect the wrists, ankles, fingers and toes.
- Enthesitis-related juvenile idiopathic arthritis. Enthesitis is a condition that is characterized by sensitivity or tenderness in the region in which the bone and tendon connect. This subtype can affect several different regions, but most often involves the hips, feet or knees. Enthesitis-related arthritis is also known as spondyloarthritis.
- Undifferentiated juvenile idiopathic arthritis. Patients are classified in the category of undifferentiated arthritis if their arthritis does not fit into any of the other subtypes, or spans across different several subtypes.