[Erythema after subcutaneous heparin treatment].

BACKGROUND: Heparin-induced skin lesions are common. The majority are delayed-type hypersensitivity reactions to heparin or other components of the injection fluid. Differentiation from heparin-induced thrombocytopenia (HIT) skin lesions is important. The Warkentin 4T's score is helpful for assessment of the risk of HIT.

CASE DESCRIPTION: A 36-year old female was treated with injections of tinzaparin for a deep vein thrombosis. After 16 days, she developed progressive thrombocytopenia and a skin lesion at one of the injection sites. She was diagnosed with "skin lesion consistent with HIT and caused by the use of low-molecular-weight heparin". The platelet count returned to normal and the severity of the skin lesion improved after replacement of tinzaparin with fondaparinux.

CONCLUSION: In patients with skin lesions suspected of being caused by the use of heparin, a complete blood count needs to be made as quickly as possible. With a 4T's score ≥ 4, it is recommended that a skin biopsy and a laboratory HIT-test are performed. Heparin should be replaced by alternative anticoagulants by way of precaution.