Acquired hemophilia.

Acquired hemophilia is a very rare disease characterized by the presence of an autoantibody (mainly IgG) to factor VIII, with a clinical presentation resembling hemophilia A. It is associated with various autoimmune or dermatologic diseases, pregnancy, cancer, or drug ingestion, but in almost 50% of patients no underlying disorder is found. The treatment of acquired hemophilia is particularly complex because response to therapy is unpredictable. If an acute hemorrhage occurs despite preventive measures, two complementary strategies must be employed: stopping the bleeding and decreasing the factor VIII inhibitor with human or porcine factor VIII, DDAVP, prothrombin complex concentrates, intravenous immunoglobulin, immunosuppression, or by extracorporeal removal of the inhibitor. Autoantibody titer, previous response to a given treatment, and severity of clinical presentation must be taken into account when choosing between these different therapeutic options, which must often be associated.