Introductions: Heparins are widely used as an anticoagulants in clinical practice. They can provoke all types of hypersensitivity reactions, although most common are delayed hypersensitivity reactions. Immediate type hypersensitivity reactions to heparin are very rare and there are only a few cases described. In this paper four cases of heparin hypersensitivity were described. Clinical manifestation, allergological work-up and further individual therapeutic recommendations were discussed. Moreover general diagnostic and therapeutic management in the case of heparin hypersensitivity was given.

Keywords: drugs hypersensivity reactions, heparines, heparin-induced thrombocytopenia, desensitization