Vasculitides

Henoch-Schönlein purpura (HSP), also known as immunoglobulin A vasculitis, is an autoimmune small-vessel vasculitis that typically presents as a tetrad of abdominal pain, arthralgia, hematuria, and purpuric rash. The pathophysiology involves the deposition of IgA immune complexes in multiple vessels following a trigger (infection/environmental), and the symptoms depend on the tissues that are involved. The diagnosis is established clinically, but can be supported with laboratory studies and skin or kidney biopsy. Management is mostly supportive, but may involve steroids and immunosuppressants in more severe cases. Prognosis is usually excellent, but some patients may develop end-stage renal failure.

Kawasaki disease (KD), also known as mucocutaneous lymph node syndrome or infantile polyarteritis, is a medium-sized necrotizing febrile vasculitis that affects children < 5 years of age. Multiple systems are involved but the most serious is the predilection of the coronary arteries. Management involves intravenous immunoglobulin and high-dose aspirin. Follow-up requires serial echocardiograms to monitor for coronary artery aneurysm.