Hives on the skin of a 61 year old female patient. Hives, also known urticaria, is a skin condition in which a rash of itchy wheals or lumps develops on the skin. Urticaria is most often caused by a non-allergic reaction to foods or drugs, although it may also be caused by heat, cold, chemicals, stress and allergies, among many other things. It can be treated with menthol cream, antihistamines or steroid tablets. Avoiding triggers can also prevent an episode of hives.