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Related to anaphylactoid: anaphylactoid purpura
A sudden, usually systemic allergic reaction, characterized by vasodilation resulting in decreased blood pressure, smooth muscle contraction resulting in shortness of breath, and hives, caused by hypersensitivity induced by a secondary exposure to a foreign substance, such as a drug or protein, after an initial sensitizing exposure.
an′a·phy·lac′tic (-lăk′tĭk), an′a·phy·lac′toid (-toid) adj.
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