Heparin-induced skin lesions

Abstract

SummaryCutaneous reactions to subcutaneous heparin injections have been described first in 1952. These reactions may be caused by several mechanisms such as immediate or delayed-type hypersensitivity responses, or by life-threatening immune-mediated heparin-induced thrombocytopenia (HIT). In contrast to bleeding, induction of osteoporosis and hair loss, no data on the incidence and causes of heparin-induced skin lesions had been available until recently. In a large prospective epidemiological study, the incidence of heparin-induced skin lesions was as high as 7.5% in medical patients, far exceeding the expected incidence. As heparin-induced skin lesions may be the sole clinical manifestation of immune HIT, rapid and valid diagnosis of heparin-induced skin lesions is of utmost clinical importance. Therefore, we have reviewed all known causes of heparin-induced skin lesions, and propose diagnostic and therapeutic procedures.

Diagnosis and Management of Heparin-Induced Thrombocytopenia

“…26-28 Patients who develop skin necrosis are a notable exception to this diagnostic rule, as thrombocytopenia frequently does not accompany this atypical manifestation. 29,30 Thrombocytopenia in HIT can present as an absolute drop in platelet count below the normal range (platelet count < 150 × 10 9 /L) or as a relative decrease of 30-50% from baseline counts. Absolute thrombocytopenia results in a moderate thrombocytopenia, with mean platelet counts of 50-70 × 10 9 /L.…”

Low incidence of heparin‐induced skin lesions in orthopedic surgery patients with low‐molecular‐weight heparins

“…The diagnosis would be corroborated further, if the skin lesions presented as necrosis or progressed towards necrosis, and/or histology showed thrombotic occlusions of dermal vessels, because there are hardly any non‐HIT explanations for the presence of necrotizing skin lesions at heparin injection sites . However, necrosis was not considered an absolute prerequisite for diagnosis of HIT, because early cutaneous erythematous reactions due to HIT and DHT may look similar . Histologic characteristics indicating other differential diagnoses were documented as well .…”

“…Skin lesions are frequent adverse reactions during subcutaneous heparin treatment. While many causes have been described for heparin‐induced skin lesions, they most commonly result from delayed‐type hypersensitivity (DHT) reactions . Prospective epidemiological investigations showed that 7.5% of medical patients treated with low‐molecular weight heparins (LMWH) develop a DTH reaction .…”

“…This may point towards a distinct risk to develop DTH responses in different patient populations. On the other hand, the second most frequent reason for skin lesions is life‐threatening immune heparin‐induced thrombocytopenia (HIT) . This complication occurs mostly in the subcohort of orthopedic and cardiovascular surgery patients rather than in medical or obstetric patients .…”

“…Of note, initial HIT‐associated skin lesions resemble clinically DTH reactions to heparins; therefore, anticoagulation must be switched immediately to a non‐heparin anticoagulant, that is danaparoid, lepirudin, argatroban, fondaparinux . Contrariwise, DTH reactions are not life‐threatening conditions but require switch to another heparin or fondaparinux as generalized reactions may occur, although cross‐allergies among different heparins are observed in >30% …”