Antiphospholipid syndrome in dermatology: an update.

Antiphospholipid syndrome (APS) is characterized by the presence of antiphospholipid antibodies, recurrent thrombosis, and fetal loss. Antiphospholipid antibodies are a family of autoantibodies that recognize various combinations of phospholipids, phospholipid-binding proteins, or both. APS can occur in the absence of underlying or associated disease (primary APS) or in combination with other diseases (secondary APS). The exact pathogenic mechanism by which these antibodies cause thrombosis is not known; however, several hypotheses, such as activation of platelet and endothelial cells and interference with the coagulation system, have been proposed. Diagnosis is based on the presence of at least one clinical and laboratory criterion each, according to International Consensus Statement on preliminary classification criteria. However, APS can be diagnosed in individuals even in the absence of some of the classification criteria. Clinical manifestations involve different organs and systems such as the blood vessels, central nervous system, skin, kidneys, gastrointestinal tract, heart, and placenta. The unifying mechanism of all these manifestations is thrombosis, either arterial or venous. Skin manifestations are varied and although not included in the diagnostic criteria, may be the presenting feature of this syndrome. Therefore all dermatologists should investigate the possibility of APS when cutaneous findings are related to venous or arterial thrombosis. The risk of thrombosis cannot be predicted, and therefore treatment is not initiated until a thrombotic event occurs. Indefinite anticoagulation is prescribed once a thrombotic event occurs. Prognosis depends on the severity of the clinical manifestations and so, knowledge of the presentation of this disease is important for early detection and prompt treatment to prevent life-threatening consequences of this catastrophic disease process.