Acquired hemophilia is a bleeding disorder that interferes with the body's blood clotting process. Signs and symptoms include prolonged bleeding, frequent nosebleeds, bruising throughout the body, solid swellings of congealed blood (hematomas), hematuria, and gastrointestinal or urologic bleeding. Acquired hemophilia occurs when the body's immune system attacks and disables a certain protein that helps the blood clot. About half of the cases are associated with other conditions, such as pregnancy, autoimmune disease, cancer, skin diseases, or allergic reactions to medications.