Disease characterized by polyarticular onset occurs in approximately 40% of patients, with a female preponderance. The majority of patients are seronegative. Seropositive patients have the worst prognosis, and the disease usually follows a chronic course similar to that in adult RA. HLA-DR4 is strongly associated with seropositive disease, but HLA-DR8 and DP3 are significantly increased in the seronegative group.

Disease with a pauciarticular onset accounts for the remaining 40% of patients with juvenile chronic arthritis. At least two subgroups are recognized within this group. One is characterized by early age of onset and female preponderance. The serum is usually positive for antinuclear antibodies but not rheumatoid factor. Patients in this subgroup are at risk for chronic iridocyclitis, which may progress to blindness. Therefore, frequent ophthalmologic evaluations should be performed. The arthritis usually resolves without deformity. HLA-DR5, HLA-DR8, and HLA-DP2 are significantly increased in this subgroup. A second subgroup with pauciarticular onset has a strong male preponderance and later age of onset. HLA-B27 occurs in the majority of these patients. The disease in these children follows a course consistent with spondyloarthropathy.

Treatment must be determined on the basis of disease severity. Aspirin is a basic standby, but tolmetin and naproxen can be used safely in children. Physical therapy and psychosocial support are also indicated.

ADULT-ONSET STILL'S DISEASE.

Still's disease is one form of juvenile-onset chronic arthritis that may begin in adulthood. Cases have been recognized that span the entire adult age spectrum, including the elderly. The clinical features are the same as those described above. Acute symptoms often respond to salicylates or other NSAIDs, but prednisone may be necessary for short periods. The prognosis for complete recovery is good in the majority of patients.