A 34-year-old woman presents to the emergency department with a 6-month history of recurrent epistaxis and easy bruising. She has experienced approximately two or three epistaxis episodes per month during this period, and the bleeds eventually stop following packing of the anterior nares. She has no past medical or surgical history and takes no medications. She has never been pregnant but notes that her menstrual periods have been "heavier than usual" during the same 6 months. She denies headaches or changes in vison. On examination, she is afebrile, has a pulse of 78 beats/minute and blood pressure of 119/82. On dermatologic examination, she has diffused areas of petechiae under her tongue, on the extensor surfaces on her forearms, and on her posterior thighs bilaterally, none of which are elevated or palpable. Abdominal exam is negative for splenomegaly. Laboratory examination shows: BUN 13 mg/dL creatinine 0.8 Mj/dL WBC 8,000 cells/mm3 Platelets 24,000 platelets/mm3 Hemoglobin 14.1 Mj/dL Hematocrit 42% PT 14 seconds (normal 11-15 seconds) Aptt 27 seconds (normal 25-40 seconds) Bleeding time 11 minutes (Normal 2-7 minutes) what is the diagnosis for this patient's condition?