Transient Passovoy defect during a febrile illness.

The Passovoy defect is a recently characterized hemorrhagic diathesis. We describe a patient with a febrile illness, possibly from Epstein-Barr (EB) virus, who acquired this defect transiently. Prothrombin time; assays for factors VIII, IX, XI, XII; and Fletcher (prekallikrein) and Fitzgerald (high molecular weight kininogen) factors were normal. No definite circulating inhibitor could be demonstrated. The transient Passovoy defect could possibly be ascribed to the infectious process or sulfisoxazole, which the patient had received.