ABSTRACT
Urticaria can be arbitrarily classified into acute (attacks of urticaria lasting less than 6 weeks), chronic (urticaria continuing on a daily or almost daily basis for 6 weeks or more), and intermittent (recurrent bouts of acute urticaria). Urticarial vasculitis will also be included in this chapter, as well as physical urticarias, urticaria pigmentosa (cutaneous mastocytosis), contact urticaria, and papular urticaria.
