Also known as melanocytic naevi

What are moles?

Moles are normal overgrowths of pigment-producing cells called melanocytes. Almost all of us have moles. They are not normally present at birth but appear in childhood and early teenage years. By the age of fifteen years, Australian children have an average of more than 50 moles. Moles have a very small risk of developing into melanoma.

What causes moles?

The number of moles that develop in an individual is predominately determined by genetic (inherited) factors and to a lesser extent by sunlight exposure. Childhood and early teenage years are the times when sunlight influences the development of new moles most strongly.

What do moles look like?

Moles are generally medium to dark brown in colour, though they range from skin coloured or pink to black. The majority of moles are flat, relatively even in colour and regular in shape.  Some moles are raised and these are usually soft to touch and lighter in colour.

Moles need to be distinguished from freckles that occur on the faces of red-headed and fair-skinned children or on the shoulders following sunburns. Moles can appear anywhere including palms and soles, nails, genitals, scalp and eyes.

How many should we have?

Australians with fair skin have large numbers of moles by world standards, perhaps because of high sun exposure in childhood. It is normal to have up to 100 moles that are 2 mm or more in size by the age of fifteen years.

What is the significance of having large numbers of moles?

Individuals with large numbers of moles (more than 100) are at greater risk of developing melanoma. As the number of moles increases, so does the risk of developing melanoma.

What are dysplastic or atypical moles?

Dysplastic moles are typically larger than other moles (larger than 5 mm) and often have a smudgy, ill-defined border, uneven colour, irregular shape and some pinkness. Some of these features may also be seen in melanomas.

Dysplastic moles are an independent risk factor for melanoma and the risk rises as their numbers increase. Dysplastic moles rarely turn into melanomas and therefore do not need to be removed routinely.

What should you do if you have a large number of moles?

If you have a large number of moles or multiple dysplastic moles, you may need to have regular skin checks. Your dermatologist may photograph your skin so that changes in your moles can be detected at follow-up visits.  Since many melanomas arise as new spots (on normal skin), it is necessary to observe all of the skin, not only the moles.

You should self-examine your skin at least every 3 to 4 months for moles that are new, growing or changing and report any significant changes to your doctor or dermatologist. It is important to avoid excessive sun exposure and protect your skin from the sun by wearing tightly woven longer sleeved clothing, broad brimmed hats and sunglasses and applying sunscreens regularly.

This information has been written by A/Prof John Kelly and Dr Yan Pan
Last updated: October 2022


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