Heparin-associated thrombocytopenia and thrombosis (HATT) presenting with livedo reticularis

Heparin-associated thrombocytopenia and thrombosis (HATT) is an infrequently encountered syndrome characterized by ischemic necrosis of soft tissue and vital organs following anticoagulation with heparin. The syndrome is thought to be due to heparin-dependent platelet aggregation and thrombosis, which is mediated by pathologic immunoglobulins.

A 60-year-old man developed truncal livedo reticularis and ischemic necrosis of the left foot associated with thrombocytopenia, disseminated intravascular coagulopathy (DIC), and microangiopathic hemolytic anemia during intravenous heparin therapy. Skin biopsy from an area of livedo reticularis revealed fibrin thrombi in dermal blood vessels, which is characteristic of HATT. The diagnosis of HATT promoted discontinuation of heparin and a resulting rapid resolution of the livedo reticularis and hematologic abnormalities. No other potential causes of DIC were identified, and, other than stopping heparin, no specific therapy was employed.

Periodic monitoring of platelets should be performed on all patients receiving treatment with heparin, as early detection of heparin-induced thrombocytopenia followed by discontinuation of the drug may prevent life threatening thrombotic complications. HATT should be included in the differential diagnosis of patients with livedo reticularis that occurs during heparin therapy.