Chronic urticaria (CU) is a disturbing allergic condition of the skin. Although frequently benign, it may sometimes be a red flag sign of a serious internal disease. A multitude of etiologies have been implicated in the causation of CU, including physical, infective, vasculitic, psychological and idiopathic. Chronic hives don't put you at any sudden risk of a serious allergic reaction (anaphylaxis). But if you do experience hives as part of a serious allergic reaction, seek emergency care. Signs and symptoms of anaphylaxis include dizziness, trouble breathing, and swelling of your lips, eyelids and tongue. Chronic idiopathic urticaria isn’t an allergy and isn’t contagious. It’s probably caused by a combination of factors. These may include something in the environment that’s irritating you, your immune system, and your genetic makeup. It can also be a response to a bacterial, fungal, or viral infection. Chronic idiopathic urticaria is an unpleasant condition, but it’s not life-threatening. Treatment with antihistamines or other medications will usually clear it up. But it may reappear when treatment is stopped.