ABSTRACT
Urticaria and angioedema may be caused by systemic disease or, theoretically, they may themselves cause systemic disease.
In practice, at least with chronic urticaria, secondary systemic manifestations are rather rare. As indicated in Chapter 13, even severe unremitting chronic urticaria with or without angioedema rarely causes systemic upset apart from psychological distress. Systemic disturbance is also rarely a problem in severe relapses of hereditary angioedema, except when secondary to bowel obstruction (see Chap. 12). Of the physical urticarias (Chap. 7), only delayed pressure urticaria is regularly associated with systemic symptoms and these are usually of a vague nature (fatigue, arthralgia). Exceptionally cold contact urticaria may cause headache, palpitations, bronchospasm, bowel disturbance, and even anaphylactic shock (symptoms suggestive of histamine toxicity) if cold exposure is extensive, as in cold water bathing. ACLlte urticaria and angioedema are more frequently associated with systemic upset, especially if the outbreak is due to an allergic cause such as IgE-mediated hypersensitivity to foods or drugs, especially penicillin. Systemic reactions in the cardiovascular system, lungs, and gastrointestinal tract may be the dominant clinical presentation and may require urgent measures (Chap. 5). This account will focus on systemic disease as a cause of, or strong association with, urticaria and angioedema.
