Juvenile Idiopathic Arthritis
1. Juvenile idiopathic arthritis (JIA) consists of several subgroups with different clinical characteristics, pathogenesis, and responses to therapy.
2. Systemic JIA (sJIA) symptoms include quotidian fever, rash, and arthritis, which respond best to interleukin (IL)-1 and IL-6 inhibition.
3. Oligoarticular JIA is characterized by young age of onset, female predominance, positive antinuclear antibody (ANA) and chronic anterior uveitis.
4. Polyarticular JIA with a positive rheumatoid factor (RF) resembles adult seropositive rheumatoid arthritis (RA).
5. ANA positivity, female sex, and age <7 years increase the risk of chronic uveitis regardless of the JIA subgroup.
6. Enthesitis-related arthritis (ERA) is characterized by lower extremity enthesitis, male sex, human leukocyte antigen-B27 (HLA-B27), acute anterior uveitis, and sometimes the later development of sacroiliitis.