Systemic Cold Urticaria
Systemic Cold Urticaria is a very rare form of Cold Urticaria. The systemic form of Cold Urticaria is seen with a generalized (other areas of body, not just area exposed) distribution of urticaria (occurring upon exposure to cold). The form was first reported in 1984. This includes Cold Urticaria occurring underneath clothed areas, usually on the trunk and extremities. The CSTT is may be positive early in development of the condition, but months or years later test negative.
Systemic Cold Urticaria (SCU) is not to be confused with Reflex Cold Urticaria or Cold Urticaria with systemic reactions. Reflex Cold Urticaria will cause an individual to have a reaction in one area other than the exposed site. With SCU, multiple areas as well as the full body, including the exposed site will display a reaction. Cold Urticaria with systemic reactions involves a localized reaction (hives at area exposed to cold) that leads to Anaphylaxis and/or shock. A systemic reaction is any reaction that disrupts two or more organ systems.