Swelling of the joints in children could be an indication of a serious illness. It could be related to an acute infection or trauma, or a chronic condition like arthritis. It is important to seek prompt medical attention if a child exhibits swelling of any joint, especially if there are no obvious causes.
When examining a swollen joint in a child, it is important to ascertain if there are other symptoms. For example fever and pain can be related to septic arthritis, an infection of the joint cavity. It is also important to determine if just one joint is swollen, or if multiple joints are involved.
Multiple joint swelling can be an indication of several autoimmune disorders in children. Juvenile idiopathic arthritis (or JIA) affects children younger than 6 years old. It has different types, depending of how many joints are involved: pauciarticular, if it affects less than four joints; polyarticular if it affects five or more joints; and systemic, which usually has other symptoms like fever and a rash before exhibiting joint swelling.
Other autoimmune diseases that cause swelling of the joints in children include systemic lupus erythematosus, a disease that can also affect the kidneys, the skin and the brain; and rheumatoid arthritis, which can follow a strep throat infection.
Trauma can also cause joint swelling in children. In young children, the traumatic event may be mild or not witnessed which can complicate or delay the diagnosis. Older children can have injuries related to accidents or sports injuries.
Septic arthritis causes swelling, redness and tenderness of the affected joint. Most children with septic joint appear ill and have fever and discomfort with the swelling. Prompt diagnosis is important to avoid long-term complications.
Diagnosis of swollen joints in children involves blood tests, including a white blood cell count (elevated in cases of infection), sedimentation rate (a non-specific marker for inflammation) and ABO titer (which checks for recent strep throat infection). X-rays are important in cases of trauma, accidents and injuries. Cases of septic arthritis need a needle aspiration of the joint space to check for the presence of bacteria.