What term describes the presence of hives on the skin?

Urticaria refers specifically to the appearance of hives on the skin, characterized by raised, itchy welts that can vary in size and may appear anywhere on the body. This skin condition occurs as a result of an allergic reaction, which causes the release of histamine and other chemicals in the body, leading to the swelling and redness associated with hives.

Pruritus, although related, refers more broadly to itching, which may or may not be caused by hives. Hypotension signifies low blood pressure, which is unrelated to the skin manifestations of urticaria. Edema involves the accumulation of fluid in the tissues, causing swelling, but does not specifically refer to the raised, itchy welts characteristic of hives. Thus, urticaria is the precise term that captures the essence of the condition described in the question.