Superficial migratory thrombophlebitis and the lupus anticoagulant.

The lupus anticoagulant is an antiphospholipid antibody found in association with systemic lupus erythematosus and in a variety of other diseases, as well as in healthy individuals. In the laboratory, the antibody interferes with the conversion of prothrombin to thrombin and prolongs the partial thromboplastin time. In vivo, it exerts a procoagulant effect resulting in thrombosis, mainly of the larger veins and arteries. The case of a young woman who developed superficial migratory thrombophlebitis in association with a high titer lupus anticoagulant is presented. Her diagnosis was initially missed because the partial thromboplastin time was not elevated. This appears to have resulted from the use of a specific thromboplastin relatively insensitive to the presence of the antibody. Retesting with a more sensitive reagent showed a markedly prolonged partial thromboplastin time.