The bruising in question is petechiae, which are the relatively large purple patches that would be seen, for example, in the extremities. There are generally several reasons for this: i. Trauma, including collisions, and even including transfusions and blood draws. Second, subcutaneous bleeding due to relatively low platelets. Third, due to thrombocytopenia of some diseases can lead to, there is also to pay great attention to is due to long-term consumption of some anticoagulants, causing some local bruising. Some of them include internal bleeding, so we should pay high attention to them, and autoimmune diseases can also be accompanied by bruising.