I bruise very easily. When I had to go on blood thinners....the heart specialist put me on them....my MD actually asked me, if I was in an abusive relationship. She had forgotten that I had been put on blood thinners.
But I bruise easily when I was not on blood thinners.
I know what you mean...plus they look strange and show up even when you have not bumped anything. I once itched my face..my friend asked me what happened to my face. I looked in the mirror and wa horrified...I looked like someone had given me a punch in the jaw. It took awhile to heal.

Medications cause bruising. I get bruises that I don't no where they came from and they takes weeks to go away. Mine are usually on my arms. Hugs and Prayers

if you are on aspirin or blood thinners they can cause bruising for no reason.

I get bruises very easily sometimes not knowing where they came from

I’m am the opposite. I seldom get bruises. If I do, I had to have hit that area really really hard. A few weeks ago I hit my back (right where my bulging disk is) on the corner of our snack bar. It caused blinding pain that brought tears to my eyes. I thought for sure there would be a bruise......nothing ever showed up 🤷🏼‍♀️