Hi there ..

Always good to ask Dr for a blood test ... could be a lot of things so don't panic .. but better to be on the safe side ... keep an eye out for more unexplained  bruising... 

Let us know how you go ... chrissie....

Most bruises are caused by minor knocks that you simply don't notice at the time.  A day later you find a bruise and wonder where it came from.  The forearm and knee are places which do get knocked easily.  Personally I wouldn't go to my GP just yet but instead keep a note of bruises that appear in the next couple of weeks.  If the existing bruises fade and no new ones appear then I wouldn't worry too much; however if more bruises appear, particularly in places which don't usually get knocked, such as the trunk, head or neck, then I'd be off to the doctor for a blood test.