Abstract
Heparins are one of the most used class of anticoagulants in daily clinical practice. Despite their widespread application immune-mediated hypersensitivity reactions to heparins are rare. Among these, the delayed-type reactions to s.c. injected heparins are well-known usually presenting as circumscribed eczematous plaques at the injection sites. In contrast, potentially life-threatening systemic immediate-type anaphylactic reactions to heparins are extremely rare. Recently, some cases of non-allergic anaphylaxis could be attributed to undesirable heparin contaminants.A 43-year-old patient developed severe anaphylaxis symptoms within 5–10 minutes after s.c. injection of enoxaparin. Titrated skin prick testing with wheal and flare responses up to an enoxaparin dilution of 1:10.000 indicated a probable allergic mechanism of the enoxaparin-induced anaphylaxis. The basophil activation test as an additional in-vitro test method was negative. Furthermore, skin prick testing showed rather broad cross-reactivity among different heparin preparations tested.In the presented case, history, symptoms, and results of skin testing strongly suggested an IgE-mediated allergic hypersensitivity against different heparins. Therefore, as safe alternative anticoagulants the patient could receive beneath coumarins the hirudins or direct thrombin inhibitors. Because these compounds have a completely different molecular structure compared with the heparin-polysaccharides.
Highlights
Heparins and heparinoids are widely used for prevention and treatment of thromboembolic diseases or during haemodialysis
Unfractionated heparin (UFH) is a heterogenous mixture of glycosaminoglycans that bind to antithrombin via a unique pentasaccharide sequence and catalyse the inactivation of thrombin, factor Xa and other clotting enzymes
In the literature we found 9 documented cases of immediate-type hypersensitivity reactions to heparins (Table 3)
Summary
Heparins and heparinoids are widely used for prevention and treatment of thromboembolic diseases or during haemodialysis. Unfractionated heparin (UFH), lowmolecular-weight heparins (LMWHs), fondaparinux, and the heparinoid danaparoid are indirect anticoagulants which require the cofactors thrombin, antithrombin, and factor Xa to exert their activity. In the patient presented an IgE-mediated allergy to heparins is suggested by convincing history and skin testing results. Case presentation A 43-year-old male patient presented to our allergy clinic after a severe anaphylactic episode for further allergologic work-up He had forgotten oral anticoagulation with phenprocoumon and alternatively injected 80 mg enoxaparin s.c. himself at home into the skin of the abdomen. Skin prick testing with the UFH heparin-sodium, LMWHs (nadroparin, dalteparin, enoxaparin), heparinoids (danaparoid, pentosan polysulfate) and fondaparinux with reading at 20 minutes revealed the strongest positive reaction to enoxaparin and additional positive reactions to heparin-sodium, nadroparin, danaparoid and fondaparinux (Table 1). A basophil activation test (BAT) with heparin-sodium, pentosan polysulfate, danaparoid, fondaparinux, dalteparin, enoxaparin and nadroparin failed to reveal any positive results
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
