F 24, left leg
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Direct immunoflourescence results:IgA and C3 deposits in the dermal vessel walls. Fibrinogen deposits in the dermis.
Henoch-Schönlein purpura (HSP) is a small-vessel vasculitis characterized by purpura, arthritis, abdominal pain, and hematuria.
HSP, a benign self-limited disorder, affects mostly (70%) children and involves the skin, GI tract, joints, scrotum and kidneys.
Etiology: Unknown, 50% may have a preceding upper respiratory infection.
Skin biopsy shows a leukocytoclastic vasculitis with perivascular infiltration of neutrophils and mononuclear cells. Necrosis of small blood vessels and platelet thrombi may also be seen.
DIF: IgA, C3, and fibrinogen deposition in arterioles, capillaries, and venules. IgA deposit is seen in purpuric skin lesions and non-lesional skin.