An atypical mole can take on several different appearances. However, a good rule of thumb when examining your skin for atypical moles is to follow the ABCDE guide (asymmetrical, borders, color, diameter, and evolving). The ABCDE guide is:
Asymmetry: One half doesn’t look like the other.
Border: Irregular or poorly defined shape or borders.
Color: Variety of colors is present.
Diameter: Bigger than 6 mm (size of a pencil eraser).
Evolving: Mole changes in size, shape, or color.
Furthermore, keep an eye out for any moles that bleed, itch, or look different than the surrounding moles. If you notice any suspicious spot or atypical mole, make an appointment for a professional skin examination with a board-certified dermatologist as soon as possible.