Cold urticaria.

Cold urticaria is probably the most common form of physical urticaria. It is usually a chronic idiopathic disorder but may be secondary to another disease characterized by abnormal serum proteins with a cold-dependent property. In delayed cold urticaria, hives appear 24 to 48 hours after cold challenge. In addition to challenge testing, the physician should obtain serologic tests to exclude the presence of associated cold agglutinins, Donath-Landsteiner antibody, cryoglobulins and cryofibrinogen.