What Causes Circular Patches On The Skin?

I ve noticed a few small, flat, circular patches on various parts of my body. They are not raised and feel kind of rough like dry skin. It is not itchy at all. However, if I DO scratch the area I noticed it is flaky. It seems very random that I would get these marks in several areas on my body (mostly the upper thigh and buttocks) out of the blue. They look like cigarette burns. Should I be worried? What can I put on it for the marks to go way? So far I ve been using Aloe Vera barbadensis jelly. Haven t been using it long enough to see any improvements.