In most cases of chronic urticaria, an underlying trigger is not found. Hodgkin's disease may be accompanied by urticaria. Cold urticaria with cryoglobulinemia is seen in multiple myeloma.

在大多数慢性麻疹患者，找不到因。霍杰氏病可有麻疹；冷球蛋白血症引起的麻疹见于多性骨髓瘤。