What Causes Round Reddish Spot On The Thigh?

i have 1 round redish spot on the side of my upper left thigh.its about the size of a quarter. it doesnt itch, its not scaly. i dont even know its there. its the only spot ive seen on my body. actually my younger daughter seen the one ive got. i didnt even know it was there. im just worried that it may be something.