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Mole on skin under magnifying glass
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Learn more about how to spot a melanoma

How to look for melanoma.

The earlier a melanoma is identified and treated, the better your chance of avoiding surgery, potential disfigurement, or even death.


How to detect a melanoma

A melanoma is a cancer of melanocytes, where cells grow independently of the body’s control mechanisms. Melanoma is the most serious form of skin cancer. If left untreated, melanoma can spread to other parts of the body. Melanoma appears as a new spot or an existing spot that changes in colour, size, shape or becomes more palpable. Melanomas tend to be asymmetrical and have multiple colours, however, some may be reddish or even skin coloured. Moles that are dark black or blue-grey in appearance may be melanoma. A melanoma can also appear on the skin not normally exposed to the sun.

ABCDE melanoma detection guide

The following guide is for detecting melanoma.

AC Image.webp

Asymmetry – Look for spots that lack symmetry.

That is, if a line was drawn through the middle, the two sides would not match up.

Border –  Benign (non-cancerous) moles have smooth and even borders. Melanomas however have irregular and hard-to-define borders.

Colour variation – Benign moles or spots tend to consist of one colour only. However, in cases of melanoma, multiple colours or shades of colour may be present. A melanoma may have blotchy spots with a number of colours such as black, blue, red, white, and/or grey.

Diameter greater than 6mm – At diagnosis, most melanomas have a diameter greater than 6mm (which is approximately the size of a pencil eraser).

Evolving or changing –  Benign moles typically do not change in shape, size, colour or structure. Meanwhile, a melanoma changes over time, which can be over months to years.


Even if a mole does not fulfil the ABCDE criteria, if it is obviously different from the other moles and spots around it, it could be considered suspicious. This is the ugly duckling rule. 

Nodular Melanoma

Nodular melanoma is a type of melanoma that grows quickly in thickness. It often looks different from common melanomas. A nodular melanoma is raised and may be even in its colour. Many are red or pink and some are brown or black. They are firm to touch and dome-shaped. After a while they can begin to itch, bleed and crust. The following image is an example of nodular melanoma.

nodular melanoma.webp

Normal moles usually look alike, so keep an eye out for any moles which may look different from others. It can be difficult to tell whether something on your skin is a sign of cancer. So, when in doubt, always speak to your doctor. It may also be helpful to talk to your general practitioner (GP) about advice on early detection of skin cancer and your level of risk.

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