Cold urticaria is a condition that affects the skin. Signs and symptoms generally include reddish, itchy welts (hives) and/or swelling when skin is exposed to the cold (i.e. cold weather or swimming in cold water). This rash is usually apparent within 2-5 minutes after exposure and can last for 1-2 hours. The exact cause of cold urticaria is poorly understood in most cases. Rarely, it may be associated with an underlying blood condition or infectious disease. Treatment generally consists of patient education, avoiding exposures that may trigger a reaction, and/or medications.