Management of childhood arthritis. Part 2: Chronic arthritis.

Classification Chronic idiopathic arthritis of childhood encompasses a diverse group of disorders. This diversity is reflected in the diVerent classification systems in use in North America and Europe. 2 As concepts have evolved there have been attempts to modify the classification system. This is not just a matter of semantics, but a recognition that it is necessary to develop as much homogeneity as possible in the groupings if there is going to be progress in understanding the cause(s), outcomes, and optimum management of childhood chronic arthritis. At present it is generally agreed that there are at least the following groups: (a) early onset oligoarticular arthritis, occurring most often in girls less than about 6 years of age, in whom there is a high risk of chronic uveitis; (b) late onset oligoarthritis, aVecting mostly older boys, often associated with enthesitis, and which is really a spondyloarthropathy and often a precursor of ankylosing spondylitis; (c) other spondyloarthropathies, a heterogeneous group of disorders, including early onset ankylosing spondylitis, reactive arthritis, and arthritis associated with inflammatory bowel disease; (d) juvenile psoriatic arthritis, which has traditionally been classified with the spondyloarthropathies, but is probably a separate group, in which there is asymmetrical small joint involvement and dactylitis; (e) polyarticular arthritis, which may be further subdivided into rheumatoid factor positive and rheumatoid factor negative subgroups; and (f) systemic onset arthritis, in which there are marked constitutional symptoms, including rash and fever.