Cold urticaria is a chronic, reactive skin disorder. It is probably the most common form of physical urticaria (hives). Major symptoms may include abnormal reddening of the skin (erythema), hives and itching after exposure of the skin to cold temperatures.
There are two forms of the disorder: essential (acquired) cold urticaria, and familial (hereditary) cold urticaria. The symptoms of the acquired form become obvious in two to five minutes after exposure to the triggering substance or situation, while it takes 24 to 48 hours for symptoms of familial cold urticaria to appear.
symptoms tend to last longer with the familial form, typically about 24 hours although they may remain for as long as 48 hours. With the acquired form, symptoms tend to last for one to two hours.
In cold urticaria, the skin has an abnormal reaction to cold. This may, for instance, occur after exposure to cold weather or to swimming in cold water. The skin usually turns red, and develops welts and itching. This may be accompanied by fever, headache, anxiety, tiredness, and, sometimes, even fainting. Some persons may also have palpitations or wheezing.
Symptoms of familial cold urticaria may begin to appear as soon as 30 minutes after exposure to cold. They may persist for up to 48 hours after exposure. The redness and itching of the skin may be accompanied by fever, headache, tiredness, pain in the joints (arthralgia), and the presence of excessive white blood cells (leucocytosis) in the blood.
Essential (acquired) cold urticaria consists, according to some clinicians, of several sub-categories such as primary acquired cold urticaria, delayed cold urticaria, localized cold urticaria, reflex cold urticaria or secondary cold urticaria, which are explained below