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. Also, 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.
Signs & Symptoms
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:
Primary acquired cold urticaria can occur five to 30 minutes after exposure to cold. The reaction may occur in the cold itself, but more often during the rewarming phase. Itching and reddening of the skin may develop first, followed by a burning sensation. Hives appear, usually lasting 30 minutes. The affected person may also experience headache, palpitations, wheezing or fainting.
Delayed cold urticaria may appear several hours after contact with the cold. Localized cold urticaria has been reported to occur after exposure to cold at the sites of previous ragweed injections for allergies or ladybug bites. Reflex cold urticaria is characterized by widespread appearance of welts occurring in response to a drop in body temperature after localized exposure to cold applications (e.g. an ice pack). Secondary cold urticaria can occur in connection with various blood disorders associated with viral infections such as mononucleosis.
Cold urticaria can occur for unknown (idiopathic) reasons, or it may be transmitted as an autosomal dominant trait. Human traits including the classic genetic diseases, are the product of the interaction of two genes for that condition, one received from the father and one from the mother. In dominant disorders, a single copy of the disease gene (received from either the mother or father) will be expressed “dominating” the other normal gene and resulting in the appearance of the disease. The risk of transmitting the disorder from affected parent to offspring is 50 percent for each pregnancy regardless of the sex of the resulting child. The risk is the same for each pregnancy.
The familial form of cold urticaria has been traced to the long arm of chromosome one (1q40). Chromosomes are found in the nucleus of all body cells. They carry the genetic characteristics of each individual. Pairs of human chromosomes are numbered from 1 through 22, with an unequal 23rd pair of X and Y chromosomes for males and two X chromosomes for females.
Each chromosome has a short arm designated as “p” and a long arm identified by the letter “q”. Chromosomes are further subdivided into bands that are numbered. For example, chromosome 1q40 refers to band 40 on the long arm of chromosome 1.
Some forms of cold urticaria are also diseases of the autoimmune system. Autoimmune disorders are caused when the body’s natural defenses against “foreign” or invading organisms (e.g., antibodies) begin to attack healthy tissue for unknown reasons. Exposure of the skin to cold triggers symptoms of the disorder. Even such commonplace activities as walking in cold weather, swimming in cold water, or even bathing in cool water may trigger an episode.
Cold urticaria affects males and females in equal numbers. Essential cold urticaria makes up about 1% to 3% of all urticaria cases, and occurs most often among young adults. Familial cold urticaria is rare.