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Formerly called Henoch-Schönlein purpura
Systemic small-vessel leukocytoclastic vasculitis associated with IgA subclass 1 deposition in vessel walls
The most common systemic vasculitis in children; often associated with an inciting infection, such as group A streptococcus
Occurs in adults as well
Classic presentation is with palpable purpura
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Purpuric skin lesions typically located on the lower extremities; may also be seen on the hands, arms, trunk, and buttocks
Joint symptoms are present in most patients; the knees and ankles are most commonly involved
Abdominal pain secondary to vasculitis of the intestinal tract is often associated with gastrointestinal bleeding
Hematuria signals the presence of a glomerular lesion that is usually reversible, although it occasionally may progress to chronic kidney disease
A decrease in GFR is common with a nephritic presentation
Renal lesions can be identical to those found in IgA nephropathy
Most patients with microscopic hematuria and minimal proteinuria recover fully over several weeks
Progressive CKD and possibly ESRD are more likely to develop in those with the nephrotic syndrome; the presence of both nephritic and nephrotic syndrome features poses the worst renal prognosis
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Chronic courses with persistent or intermittent skin disease are more likely to occur in adults than children
The efficacy of treatment is not well established
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 such as mycophenolate mofetil, but there is no consensus as to the efficacy of this approach or the optimal therapeutic regimen
Rituximab treatment and plasma exchange have been successful for severe nephritic disease according to case reports, but clinical trials are lacking
Rapidly progressive renal disease with crescent formation on biopsy may be treated as in ANCA-associated vasculitis