Leukocytoclastic vasculitis is characterized by infiltration of polymorphonuclear leucocytes with leukocytoclastic (presence of nuclear pigments) and fibrinoid necrosis affecting the small vessels. Henoch-Schönlein purpura is characterized by non thrombocytopenic purpura, arthritis and arthralgia, abdominal pain and renal involvement. Hypocomplementemic urticarial vasculitis and cryoglobulinemia are exceptional in childhood.