Allergic heparin hypersensitivity – recommendations for diagnostic work up and patient management

This article provides an overview of selected scientific articles and is based on a  literature search in PubMed and specialist databases.ResultsMost commonly, heparin allergic patients develop lymphocyte-mediated, eczematous local reactions directly at the injection sites (usually on the lower abdomen) hours to days after initiating regular subcutaneous heparin injections. The high sensitivity of skin-prick and intradermal testing procedures means that subcutaneous provocation tests are seldom necessary for diagnosis. The “compartment allergy” phenomenon is a particular feature of heparin-induced local allergic reactions. Here, the route of application determines whether an allergic inflammatory reaction develops. In case of heparin-allergic individuals, injections into the subcutaneous tissue cause eczematous p laques, whereas intravenous injections or infusions are well tolerated. Since the introduction of low molecular weight heparin preparations, the incidence of potentially life-threatening heparin-induced thrombocytopenia caused by activating IgG (Ig: immunoglobulin) antibodies against heparin-platele t factor 4 (PF4) complexes on platelet membranes has declined. IgE-mediated heparin allergy with immediate-type anaphylactic reactions seems to be extremely rare.
Source: Allergo Journal International - Category: Allergy & Immunology Source Type: research