The A.B.C.D. rule has been very effective at aiding the early identification of superficial spreading melanomas. Superficial spreading melanoma can have any one of the following criteria:


ASYMMETRY: The shape of one half does not match the other.

BORDER: The edges are often ragged, notched, blurred, or irregular in outline; the pigment may spread into the surrounding skin.

COLOUR: The colour is uneven. Shades of black, brown, and tan may be present. Areas of white, grey, red, pink, or blue also may be seen.

DIAMETER: Size changes and usually increases. Typically, melanomas are at least 6mm in diameter (the diameter of a pencil).


There is a class of rapidly growing, nodular melanoma, which represent about 20% of all cases of melanoma. This type of melanoma does not subscribe to the ABCD rule and thus can go undetected. Fortunately, they do behave in a way that allows them to be identified early using the E.F.G. rule. Nodular melanoma usually have all three of the below criteria:



The moles don’t need to be dark or have any other colour to them, but the key giveaway is that they are raised, often very symmetrical, are firm to touch, and most importantly are changing/growing progressively. In the early stages, this change might just be a sense of change rather than visible – perhaps the mole is itchy, or just feels funny. This type of melanoma can affect anyone, but is generally much more common in men over 50. The frightening thing about nodular melanoma is that because they are growing fast, they can go deep very quickly (within a few months), which is why they are so dangerous and need early diagnosis and removal.

Melanoma does not always fit the A.B.C.D. or E.F.G. rules described above

If you notice a lesion that is:

  • Different from others (The Ugly Duckling)
  • Changing in shape, size or colour
  • A new skin lesion
  • Itching or bleeding

You should bring it to the attention of your doctor or MoleMap immediately, accurately describing the symptoms and your reason for concern. Call 1800 665 362.