Identification of patients at risk for anaphylaxis due to streptokinase.

To identify patients at risk for immediate-type allergic reactions to streptokinase, we performed streptokinase skin tests on patients immediately before planned administration of intravenous streptokinase for treatment of acute myocardial infarction. Forty-five patients had negative skin tests and received streptokinase without allergic reaction. One patient had a positive skin test and was given urokinase instead, without incident. Positive skin tests were also present in a patient who had recently had an anaphylactic reaction to streptokinase, and in two physician volunteers who had been sensitized to streptokinase during initial determination of the optimal skin testing dose. Immunoassays for IgE to streptokinase were performed on serum samples from skin-tested patients and volunteers, and on 16 other patients who had not been skin tested but had previously received streptokinase without allergic reactions. The skin test was a sensitive and specific indicator of elevated levels of IgE to streptokinase. We propose that skin testing immediately before streptokinase administration is a practical approach for identifying patients at risk for immediate-type allergic reactions to streptokinase, and its use may possibly prevent anaphylaxis and death.