Brown splotches

I am a 47 year old female. For quite some time, I've had several brown splotches appearing on my ankles and lower legs.These brown splotches remind me of age spots that I've seen on older women's hands or face. They do not hurt, itch, burn or have any type symptom other than ugly, The splotches are not like blisters or whelps. They are flat and you can not feel them when you rub your hand across them. They started out around my ankles and are now moving up toward my knees. I don't know any other way to describe them other than big brown splotchy areas. I can't find any information anywhere that might suggest what's caused this and how to treat it.  Can you help me?