20-25: IgA Vasculitis (Henoch-Schönlein Purpura)

IgA vasculitis (Henoch-Schönlein purpura), the most common systemic vasculitis in children, occurs in adults as well. Typical clinical features are palpable purpura, arthritis, and hematuria. Abdominal pain occurs less frequently in adults than in children. Pathologic features on skin biopsy include leukocytoclastic vasculitis with IgA deposition. Biopsy of the kidney reveals segmental glomerulonephritis with crescents and mesangial deposition of IgA. 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 GI bleeding. Hematuria signals the presence of a renal lesion that is usually reversible, although it occasionally may progress to CKD (see Henoch-Schönlein purpura, Chapter 22). Children tend to have more frequent and more serious GI vasculitis, whereas adults more often suffer from glomerulonephritis. 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. Given the success of rituximab in treating other forms of vasculitis, it has been used for the treatment of IgA vasculitis with some success, although this indication does not have FDA approval.