What are the ABCD rules of melanoma?

A - Asymmetry: One half of the mole does not match the other half.

B - Border: The edges of the mole are irregular, ragged, notched, or blurred.

C - Colour: The colour of the mole is not uniform and may include shades of brown or black, or sometimes with patches of pink, red, white, or blue.

D - Diameter: The mole is larger than 6 millimetres in diameter (about the size of a pencil eraser).