Take pictures. See an actual MD and have them diagnose.

Not sensible to crowdsource this kind of question.

actinic purpura?

Have you taken pictures of the splotches when they occur? Maybe you could try a reverse image search to help identify them? Any other odd symptoms?

I first noticed this whe I was 60 and I asked my doctor about them. She said I was just getting older.

60yo male. For the past 18 months or so randomly get a skin splotch what initially looks look like an unexplained bruise but within hours turns red and then slowly fades away within a 3-4 days. The size varies from 1/4 to 1/2 inch and usually oval. Not painful nor raised and always on the arms or legs, thighs. Frequency would be one every two months or so and never more than one at a time. I have been to PC and derm and they unable to diagnose. They ran a blood clotting test and all ok with that. No other symptoms. Anyone else seen this strange condition? Could it be an allergic reaction to something ?