IgA vasculitis (Henoch-Schönlein purpura), the most common systemic vasculitis in children, occurs in adults as well. Typical features are palpable purpura, arthritis, and hematuria. Abdominal pain occurs less frequently in adults than in children. Pathologic features include leukocytoclastic vasculitis with IgA deposition. The cause is not known.
The purpuric skin lesions are typically located on the lower extremities but may also be seen on the hands, arms, trunk, and buttocks. Joint symptoms are present in the majority of patients, with the knees and ankles being most commonly involved. Abdominal pain secondary to vasculitis of the intestinal tract is often associated with gastrointestinal bleeding. Hematuria signals the presence of a renal lesion that is usually reversible, although it occasionally may progress to chronic kidney disease. Children tend to have more frequent and more serious gastrointestinal vasculitis, whereas adults more often suffer from chronic kidney disease. Biopsy of the kidney reveals segmental glomerulonephritis with crescents and mesangial deposition of IgA. Chronic courses with persistent or intermittent skin disease are more likely to occur in adults than in children.
The value of corticosteroids has been controversial. In children, prednisone (1–2 mg/kg/day orally) does not decrease the frequency of proteinuria 1 year after onset of disease. Severe disease is often treated with aggressive immunosuppressive agents, but there is no consensus regarding the efficacy of this approach or the optimal therapeutic regimen.
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