Urticaria, or hives, is most commonly seen on the skin surface, but can also occur subcutaneously and on the oral mucosa. A distinguishing feature of urticaria, which can be confused with angioedema, is that it is itchy and lasts longer. Angioedema, in contrast to urticaria, frequently affects the face and lips and can cause pain and burning. Unlike urticaria, it does not respond favorably to antihistamines.