For detecting early signs of melanoma, follow the ABCDEs of skin cancer when you are examining your skin. If you notice any of the following, you should have your skin checked out by a dermatologist:
Asymmetry: If you draw a line through the middle of the mole or dark spot on your skin, you do not have matching halves.
Border: A mole with an irregular, scalloped, or faded border.
Color: The color of the mole is inconsistent, with shades of tan, brown, red, black, dark brown, or blue.
Diameter: Melanomas are typically larger than 6mm (the size of a pencil eraser).
Evolving: A mole or skin growth that looks different from other moles on your body or changes in appearance.