A. B. Götz’s research while affiliated with Ludwig-Maximilians-Universität in Munich and other places

Background Delayed type allergy to heparin, which can cause skin reactions to subcutaneously administered heparin, is not rare. If further heparin therapy is necessary, management is problematic. Case reports We report the cases of two female patients who had developed erythematous infiltrations at the injection sites of subcutaneously applied heparin. Few days before an urgent bypass operation, the patients presented for allergologic diagnostics to assess what intraoperative antithrombotic treatment could be used. Allergological investigations revealed erythematous infiltrations typical of delayed-type reactions to the intradermal test with heparin sodium and to the subcutaneous challenge with danaparoid sodium, which had been considered to be used as a substitute for heparin. Considering all circumstances, intravenous administration of heparin sodium was chosen as the most reliable anticoagulant regimen despite the allergic reaction to subcutaneous heparin. After intravenous premedication with corticosteroids and H1- and H2-blocking antihistamines, intravenous heparin sodium was tolerated without reaction intraoperatively. Conclusions In both patients intravenous heparin was tolerated despite a delayed type reaction to subcutaneously administered heparin. As such tolerance is not predictable, careful consideration of risk and benefit as well as careful observation of the patient are necessary in case this approach is used.