title: Allergic anaphylaxis due to subcutaneously injected heparin.
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.
authors.affiliation: Department of Dermatology, Venereology, and Allergology, University Hospital of Würzburg, Josef-Schneider-Str, 2, Würzburg, 97080, Germany. Anders_D@klinik.uni-wuerzburg.de.
authors.forename: Diana
authors.initials: D
authors.lastname: Anders
authors.forename: Axel
authors.initials: A
authors.lastname: Trautmann