I have had this from prednisone - sometimes it is better, but any scratch or bump can cause this - for me. It also appears out of no where without any injury. I have used Dermend moisturizing bruise formula cream. (I am not compensated at all for this). It has helped me sometimes, if I put this on as soon as the blood bruise appears. Hope this is helpful. I have also heard of arnica cream, but that does not help me as much.