What Causes Circular Patch On The Foot Near The Ankle?

I have a circular patch on the front of my right foot at ankle level that is roughly the size of a quarter. The coloring is like that of an old bruise. It started much smaller about 8 months ago. It doesn't itch, but it's raised somewhat. It shows up worse after sun exposure or a hot shower. Also, on the opposite ankle, just where the left ankle bone touches the spot on the right foot if i cross my legs at the ankle, I have another, smaller spot that is much newer. It's not uncomfortable but it's unsightly. Is it a fungus? Or something else?