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Moles

Published by Bupa's health information team, February 2008.

This factsheet is for people who have moles, or who would like information about them.

A mole (melanocytic naevus or melanonaevus, plural naevi) is a small, dark area of skin. Moles are usually circular or oval-shaped. They may be present at birth, but most appear later. They may change shape or colour over time and some may even drop off completely.

Moles are usually harmless but sometimes they can become cancerous.

What are moles?

Moles are areas of skin where cells called melanocytes have grouped together. Melanocytes produce a pigment called melanin which gives your skin its colour - where they cluster together the skin is darker. You may have moles when you are born, but they usually develop later, mostly during the first 20 years of life.

Moles vary in colour from flesh-coloured to dark brown. They may be raised or have hairs growing out of them.

Types of moles

There are many different types of moles. Some types look very similar to one another and it can be hard to tell them apart. They may also be confused with other skin conditions such as freckles and warts.

Moles that you are born with are called congenital moles. They are usually at least 1cm across but can be much bigger. As you grow, they tend to grow with you and may become more raised and hairier as you get older.

Moles that appear after you are born are called acquired moles. Some of the different types are described here.

  • Junctional melanocytic naevi are flat and round. They are usually mid to dark brown.
  • Compound melanocytic naevi are slightly raised and are often hairy. Their colour can vary.
  • If you have intradermal naevi, they are likely to be dome-shaped and look a bit like compound naevi. They may not be any darker than the rest of your skin.
  • You may have a blue naevus - these are blue and are usually found on your hands or feet.
  • Children and teenagers may have halo naevi. These moles have a pale ring around them and may go away by themselves.
  • Dysplastic naevi often appear in groups. They are likely to be larger than other moles and may vary in shape, size and colour.

You may develop seborrhoeic keratoses/warts later in life. They aren't actually moles, although they are often a similar colour. They are also nothing to do with your sebaceous glands (these secrete an oily substance), but are caused when ordinary skin cells build up. They may look as though they have been stuck on.

Symptoms

Most moles are harmless and won't cause you any problems. However, you may find that some catch on clothes or jewellery. You may also have a mole that becomes sore or inflamed.

Complications

Certain types of moles are more likely to develop into skin cancer.

  • If you have a congenital melanocytic naevus, there is a one in 20 risk that it may become cancerous.
  • Dysplastic naevi are more likely to progress into a malignant melanoma (a type of cancer).

It's a good idea to check your moles regularly so that you are aware if any of them change shape or colour. You should see your GP if you notice:

  • growth of an existing mole
  • a mole with a ragged/uneven edge
  • a mole of varying shades of colour
  • a mole that bleeds, oozes or crusts
  • a mole that feels painful or itches
  • a mole where the two halves don't look the same

An easy way to remember these changes and what to do if you notice any of them is to use the ABCDE method.

A - asymmetry
B - border
C - colour
D - diameter
E - expert

Causes

The exact reasons why you may develop moles are not fully understood at present. However, many types seem to run in families, particularly dysplastic naevi. The likelihood of having lots of moles also seems to be inherited.

You are more likely to have moles if you spend lots of time in the sun, especially if you have done so since childhood.

If you have fair skin you will probably have more moles.

Moles can also appear because of changes in your hormones. This commonly occurs:

  • during adolescence
  • if you are taking the contraceptive pill
  • during pregnancy
  • during the menopause

Diagnosis

Most moles are harmless, but if you have any moles that change size, shape or colour it's a good idea to see your GP. You should also speak to him or her if a mole becomes painful or starts to bleed. Your GP will ask about your symptoms and examine you. He or she may also ask about your medical history, including whether anyone in your family has had skin cancer.

Some GP surgeries have special cameras and will take a photo of your mole so that at your next appointment your GP can see if it has changed at all. This is called mole mapping. There are also lots of clinics that offer a mole mapping service.

You may have a biopsy done on your mole. A biopsy is a small sample of tissue. This will be sent to a laboratory for testing.

It's possible that you will be referred to a dermatologist - a doctor who specialises in identifying and treating skin conditions - who can carry out further tests.

Treatment

Even if your mole is not cancerous, you may still decide to have it removed. Your mole may be annoying if it catches on things. You may also wish to have it removed for cosmetic reasons.

The procedure that is used to remove your mole will vary depending on what type you have.

  • If you have a shave biopsy, you will just have the top layer of skin taken off using a blade.
  • If you need to have deeper tissue removed, you may have a punch biopsy to remove a disk of skin.
  • An excision biopsy involves removing the whole mole.

You may need to have stitches depending on the size of the mole and whether any of the surrounding skin cells are removed. If it's smaller, your surgeon may just burn (cauterise) the area underneath where the mole was. You will be given a local anaesthetic before any of these procedures are done. This completely blocks feeling from the area and you will stay awake during the operation.

You may also have a mole frozen off using liquid nitrogen. This is called cryotherapy.

Prevention of skin cancer

It's important that you take care to look after your skin when you are out in the sun. This can help to prevent sunburn which can increase your chance of developing skin cancer. When you are out in the sun, some tips to remember include:

  • wearing at least SPF15 sunscreen
  • covering up with a hat, T-shirt and sunglasses
  • staying out of the sun at the hottest times of the day (usually between 11am and 3pm)
  • taking particular care of babies and children as sun exposure in early life is especially harmful

Further information

 

Related topics

Sources

  • Simon C, Everitt H, Kendrick T. Oxford Handbook of General Practice. 2nd ed. Oxford: Oxford University Press, 2007:664
  • Pigmented lesions - ephelides, lentigines, melanocytic nevi and melanomas. American Academy of Dermatology.
    www.aad.org
    accessed 5 September 2007
  • Melanoma. British Association of Dermatologists.
    www.bad.org.uk
    accessed 6 September 2007
  • Seborrhoeic warts. British Association of Dermatologists.
    www.bad.org.uk
    accessed 5 September 2007
  • Actinic keratoses - also known as solar keratoses. British Association of Dermatologists.
    www.bad.org.uk
    accessed 5 September 2007
  • Detecting skin cancer. Cancer Research UK.
    http://info.cancerresearchuk.org
    accessed 6 September 2007
  • Moles. American Academy of Dermatology.
    www.aad.org
    accessed 6 September 2007
  • Tests for skin cancer. CancerHelp.
    www.cancerhelp.org.uk
    accessed 6 September 2007
  • Sun protection on holiday. Cancer Research UK.
    http://info.cancerresearchuk.org
    accessed 6 September 2007
  • Skin cancer. British Skin Foundation.
    www.britishskinfoundation.org.uk
    accessed 6 September 2007

This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Dr James Quekett Bsc MBChB MRCGP DRCOG DFFP, General Practitioner (GP) and GP Appraiser, Gloucestershire, and by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.

Publication date: February 2008.

 

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