Version July 2025
| Systemic JIA | Oligoarticular JIA | Polyarticular JIA | |
| % of JIA patients | 10 to 15 | 50 | 30 to 40 |
| Sex | F = M | F>M | F>M |
| Age | <17 years, but adult-onset Still's disease can occur in older patients | Peak 2 to 3 years, rare >10 | Peaks 2 to 5, 10 to 14 years |
| Joints | Any number and any joint | 4 or fewer large joints, but rarely hips; may extend to involve more joints | Any joint, usually symmetrical, and must involve more than 5 joints |
| Fever, rash, lymphadenopathy, hepatosplenomegaly | Yes | No | No |
| Uveitis | Rare | 20%; most common in patients who are ANA positive | 10 to 20%; most common in patients who are ANA positive |
| Laboratory abnormalities | |||
| Elevated with neutrophil predominance | Normal | Normal |
| Commonly low | Normal | Normal |
| Very elevated, unless there is MAS (paradoxically drops due to fibrinogen consumption) | Usually not elevated | May be mild to moderately elevated |
| Negative | Positive low titer (1:40 to 1:80) common | Positive low titer (1:40 to 1:80) common, especially in younger children |
| Negative | Negative | 10 to 20% in those >10 years |
| Commonly extremely elevated (often >1000 ng/mL) | Normal | May be mildly elevated |
| Response to methotrexate | Poor to moderate | Excellent | Excellent |
| Response to biologic drugs | Poor to TNF inhibitors Excellent to IL-1 and IL-6 inhibitors | Excellent to TNF inhibitors and IL-6 inhibitors Poor to IL-1 inhibitors | Excellent to TNF inhibitors and IL-6 inhibitors Poor to IL-1 inhibitors |
