Anaphylaxis

SYSTEMIC anaphylaxis represents the most dramatic and potentially catastrophic manifestation of immediate hypersensitivity. This syndrome can affect virtually any organ in the body, although reactions involving the pulmonary, circulatory, cutaneous, neurologic, and gastrointestinal systems are the most common. Reactions range widely in severity from mild pruritus and urticaria to shock and death. Despite recent advancements in our understanding of the mechanisms and mediators involved in these events, the typically explosive and unforeseen nature of severe reactions often hampers treatment. As a result, anaphylaxis occurs in the United States at rates estimated to be as high as once in every 3000.