Hi, I had gone through your question and understand your concerns. It is pretty unusual to see such abrasions if there was no injury I must admit. There may have been unnoticed injury. If not, then it may be sign of circulatory issues and leg artery atherosclerosis and this is called arterial ulcer then. So at this point you should keep it clean, apply mild neutral cream such as Aquagel or Granuflex and see if this is gonna heal. If not, then you need to do Doppler ultrasound or angiography to rule out these vascular issues. Second cause may be autoimmune disorder but this is much less common. Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions. Wishing you good health.