Delayed hypersensitivity at the injection sites of a low‐molecular‐weight heparin

Abstract

We report a case of delayed hypersensitivity to a low-molecular-weight heparin. The patient presented with eczema at the site of subcutaneous injections and allergy tests confirmed the clinical diagnosis. There were positive tests with 3 low-molecular-weight heparins and unfractionated subcutaneous calcium heparin but negative with intravenous sodium heparin. Although delayed hypersensitivity to low-molecular-weight heparins is rare, the possibility of cross-allergy to unfractionated heparin could be a therapeutic problem for some patients.