Spättyp-Allergie gegen Heparin : Klinik - Diagnostik - Ausweichpräparate

Delayed hypersensitivity reactions resulting from subcutaneously injected heparin are observed not infrequently among patients requiring anticoagulation. Very often these patients tolerate neither high nor low molecular weight heparins. Therapeutic alternatives on the current pharmaceutical market are the heparinoid Orgaran® and the synthetic pentosanpolysulphate Fibrezym®. In 11 patients suspected of delayed hypersensitivity reactions to heparin we performed patch, prick, intradermal as well as subcutaneous provocation tests using heparin and the above mentioned alternative drugs. All 11 patients showed sensitization to all low and high molecular weight heparin preparations tested. Characteristicaly, positive reactions occured after 72 - 96 h. Skin tests and subcutaneous exposure of the alternative drugs showed that only 2/11 patients tolerated the heparinoid Orgaran®, whereas 6/11 patients tolerated pentosanpolysulphate. The preservative chlorocresol, added to some heparin preparations, was not the cause of the observed hypersensitivity reactions. In spite of a proven hypersensitivity to s.c. adminstered heparin in one patient who required open heart surgery, we intravenary challenged the patient with heparin. This was tolerated well, without any premedication.