A study of coagulation and anti-endothelial antibodies in idiopathic livedo reticularis

Livedo reticularis is associated with collagen vascular diseases and other vaso-occlusive disorders in a substantial number of cases. In the remaining cases the cause of livedo reticularis is still unknown. (i.e., idiopathic). We sought to determine a possible causal relationship between idiopathic livedo reticularis and autoimmune factors associated with the coagulation system, including antiendothelial cell antibodies. Nine patients with idiopathic livedo reticularis were studied. All patients were found to have normal platelet count, fibrinogen levels, and prothrombin and activated partial thromboplastin times, as well as negative results for Venereal Disease Research Laboratory and D-timer tests. Anticoagulant activity was detected in 2 patients: one had positive results of thromboplastin titration index and Russell's viper venom test, as well as increased levels of anticardiolipin antibodies and anti-endothelial cell antibodies; the other has positive thromboplastin titration index, mildly increased levels of anti-endothelial cell antibodies, and markedly increased levels of antinuclear antibodies. A third patient had mildly increased levels of anti-endothelial cell antibodies alone, and a fourth patient had mildly increased levels of antinuclear antibodies only. The clinical outcome was uneventful in all of the patients during an 18-month follow-up period. These findings suggest involvement of autoimmune factors associated with the coagulation system in some patients with idiopathic livedo reticularis, whose clinical significance remains to be determined.