Oligoarticular juvenile idiopathic arthritis (JIA), also known as oligoarthritis, is the most common and often the mildest type of JIA. Oligoarticular JIA most commonly affects the knees, ankles, fingers, toes, wrists, elbows, and hips.

Oligoarticular JIA affects 4 or fewer joints during the first 6 months of the disease. Symptoms tend to be limited to joint swelling and pain. But it can also include uneven bone growth. This can lead to one leg being longer than the other. As it progresses, this type of JIA can develop into:

• Persistent oligoarthritis, maintaining a mild level of disease, with 4 or fewer joints affected.
• Extended oligoarthritis, affecting 5 or more joints after the first 6 months of disease, with a course much like polyarticular JIA.

Whole-body (systemic) symptoms (such as weakness, fatigue, and fever) are not common.

Children with oligoarticular JIA have a high risk for inflammatory eye disease. This can lead to blindness. Eye damage can occur without causing symptoms. So frequent eye examinations are needed.

In the past, oligoarticular JIA was known as pauciarticular JIA.