[Urticarial vasculitis]

Urticarial vasculitis is defined by association of an urticaria and/or angio oedema and a vasculitis of the small dermal vessels, leucocytoclastic or mononuclear. Sometimes it is an acute urticaria, of infectious or drug origin. Urticarian vasculitis may also be due to pressure or cold. But usually, it is a chronic urticaria that readily accompanies systemic signs and immunological anomalies, in particular hypocomplementemia. The clinical-biological picture becomes a true entity or is associated with another condition, most often a collagenosis.