What is cold urticaria?

• A. "Cold hives" occurring on the skin after exposure to cold stimulus.
• B. An allergy to heat that causes hives.
• C. Numbness following cold exposure.
• D. Vasospasm of skin blood vessels.

Answer: (A)

Cold urticaria is a physical reaction where hives (welts) appear on the skin after exposure to cold stimuli, such as cold air, water, or handling cold objects. The hallmark is itchy, red welts that develop at the sites of contact within minutes of cold exposure and typically fade within an hour. This happens because cold triggers release of histamine from skin mast cells, leading to the urticarial reaction. Some people may have swelling of surrounding tissue and, in more exposed or larger-area exposures, even systemic symptoms if the whole body is cooled (like swimming in cold water).

This matches the idea of “cold hives occurring on the skin after exposure to cold stimulus.” The other options describe different conditions—an allergy to heat would involve heat-triggered hives, numbness after cold points to frostbite or nerve injury, and vasospasm of skin vessels aligns with Raynaud phenomenon—so they aren’t about urticaria. Diagnostics can include a simple ice cube test, and management centers on avoiding cold exposure and using antihistamines; severe cases require medical supervision.