Suggest Remedy For Rashes

I have what appears to be a rash on both my shins. There are blotchy areas consisting of tiny red dots, they range in size from a pencil eraser to about 2 x 1 inches. They do not itch, they are not raised, have no borders, they are not dry or scaly and only appear on the front and sides of my lower legs. I first noticed one spot the size of a pencil eraser near my ankle about a month ago and a few days later they are all over my shins. I thought maybe it could have been from shaving with a disposable razor but it has not improved with using a brand new razor each time. My diet, detergent, lotions, soaps have not changed. What could this unusual rash be?