A freckle is a small brown spot on your skin, caused by sun exposure. Use your abcde's to tell the difference between a freckle and skin cancer. A=asymmetry. B=border [irregular]. C=color [irregular]. D=diameter [larger than a pencil eraser]. E=evolving [change in color, size, height, new symptoms like bleeding, itching or crusting]. These are danger signs that freckles do not have.