Moles or Naevi

What are moles?

Moles, known medically as melanocytic naevi, are very common, harmless growths made up of clusters of pigment cells called melanocytes. Most people have some moles, and they tend to be more numerous and more visible on lighter skin.

Who gets them?

A few moles are there from birth or the first couple of years of life (congenital naevi). Most, however, develop through childhood, the teenage years and early adult life. Mole numbers tend to rise until the 30s or 40s. After that, moles may slowly flatten, lighten or fade away.

What causes them?

Moles develop when melanocytes grow in clusters rather than being spread evenly through the skin. The number of moles a person develops is influenced mainly by their genes and by sun exposure, particularly sunburn in childhood.

Are they hereditary or contagious?

The tendency to have many moles, including atypical moles, runs in families. Moles are not contagious.

What do they look and feel like?

Moles vary widely. They can be flat or raised, smooth or rough, and range from skin-coloured or pink to light brown, dark brown or black. Some contain hairs. Most are round or oval, have a smooth, regular edge and a single, even colour, and are smaller than about 6 mm across. A person's moles usually look similar to one another. Flat, evenly coloured moles are called junctional naevi; raised brown moles, sometimes hairy or warty, are compound naevi; and raised, paler moles are intradermal naevi.

Atypical or dysplastic moles are moles with an unusual appearance. They are often larger, with irregular edges and a mixture of colours. They are usually harmless, but having many of them is associated with a higher risk of melanoma. Some people have a large number of atypical moles, called atypical mole syndrome.

How are they diagnosed?

Moles are examined with a dermatoscope, a hand-held magnifying device with a light that allows a much more detailed view of the pigment pattern and structures within a mole than the naked eye. For people with many moles or a higher risk of melanoma, mole mapping uses photographs to record the whole skin and individual moles, so that changes can be detected at later checks. If a mole is concerning, it may be removed and examined under the microscope.

What are the treatment options?

Dr Mounsey will examine your moles with a dermatoscope and can carry out a full skin check. Most moles are harmless and need no treatment. A mole that looks unusual or is changing can be removed and examined under the microscope, which he carries out himself by skin excision. Harmless moles can also be taken off for cosmetic reasons, either by shave excision for raised moles or by full excision, and he will explain the likely scar. For people with many moles, mole mapping with the Canfield IntelliStudio can help track changes over time.

What is the outlook?

Most moles are harmless and stay that way throughout life. They do not need to be removed unless they look concerning or are causing problems, for example by catching on clothing.

Moles and melanoma risk

The vast majority of moles never become cancerous. However, melanoma can develop within an existing mole or, more often, as a new mark. Melanoma risk rises with a high mole count (over about 100), with several atypical moles, with a family or personal history of melanoma, with fair skin that burns easily or red or fair hair, and with past sunburn or sunbed use.

When should a mole be checked?

You should have a mole checked if it is new and you are an adult; it is changing in size, shape, colour or height; it has an irregular, ragged or blurred edge; it has several colours or an uneven colour; it is bleeding, crusting, itching or painful; it looks different from your other moles (sometimes called the ugly duckling sign); or a dark streak has appeared in a nail.

Checking your skin regularly, around once a month, and taking photographs can help you notice changes. A partner, friend or family member can help with areas that are difficult to see, such as the back and scalp.

More information

British Association of Dermatologists patient leaflet: https://www.bad.org.uk/pils/melanocytic-naevi-pigmented-moles

British Association of Dermatologists patient leaflet on atypical mole syndrome: https://www.bad.org.uk/pils/atypical-mole-syndrome

This page gives general information only and is not a substitute for a consultation. Everyone's skin is different, and what is right for you will depend on your own circumstances. If you are worried about a skin problem, please book an appointment with Dr Mounsey or speak to your GP. If you have a mole or skin lesion that is changing, bleeding or growing quickly, please seek medical advice promptly.