What type of juvenile idiopathic arthritis is characterized by involvement of ≤4 joints?

Oligoarticular juvenile idiopathic arthritis (JIA) is specifically defined by the involvement of four or fewer joints during the first six months of the disease. This type of JIA often presents in early childhood and typically affects large joints such as the knees, ankles, and elbows. It is important to distinguish oligoarticular from polyarticular JIA, which involves five or more joints at any time during the disease course.

Children with oligoarticular JIA may also have a risk of developing uveitis, an eye condition that can lead to vision problems if not monitored and treated appropriately. The early identification of oligoarticular JIA is crucial for effective management and to prevent any long-term complications.

Thus, the characterization of joint involvement in oligoarticular JIA is definitive in identifying this form of juvenile idiopathic arthritis.