Drug-induced urticaria

The occurrence of acute urticaria during treatment with drugs is a frequent event which poses two problems: 1) is the urticaria connected with the dru g administration or with the underlying pathology which led to the prescrip tion of the drug; 2) is the urticaria allergic in origin, i.e, due to speci fic immunity triggers, in particular IgE directed against the drug, or is t he urticaria pseudo-allergic in origin, i.e. due to non-specific activation of mastocytes [1]? This question is of major importance because allergic e vents caused by IgE are potentially fatal while pseudo-allergic events are only rarely life-threatening. In this article we will not deal with contact urticaria where the cause is easily identifiable [2].