Antibody-mediated reactions diagnosis

Answers to questions 3, 4, 5, and 7 can go a long way toward helping to establish a firm diagnosis. In relation to points 4 and 5, information on the temporal sequence of events can provide essential information needed to help determine the mechanism of the reaction. Immediate, IgE-antibody-mediated reactions that can range from a simple rash to full-blown anaphylaxis generally occur from only a few minutes to 1 h after drug administration. Delayed or late reactions may occur from more than 1 h up to several days after... 

Investigations were also needed to establish the mechanisms underlying these reactions, the most important of all questions. In some of the patients (five of the ten patients we have reported Assem 1977 a) a history of prior exposure to Althesin without undue reaction was obtained, thus favouring the diagnosis of classic immediate allergy, i. e., a reaction presumably mediated by anaphylactic antibodies (IgE mainly, but possibly IgG subclasses as well). Furthermore, a history of other allergies, particularly atopic conditions, was commonly obtained in patients reacting to Althesin. In the patients in whom a history of previous exposure was not obtained, the acute reaction was unlikely to be due to an immune mechanism. Thus,... 

As always, a meticulously recorded and studied history is desirable, but additional clinical and laboratory tests can contribute greatly to an accurate diagnosis and help to identify the mechanism(s) of the reaction. Skin tests, detection, and quantitation of released mediators and serum IgE antibodies may all contribute to establishing a more precise diagnosis of an adverse response to an iodinated contrast medium. 

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