Moles
Introduction
Moles, also known as melanocytic naevi, are small skin lesions that are usually brown. They are a collection of cells that produce pigment (colour) in your skin.
Moles are usually a brownish colour, although some may be darker or skin-coloured. Moles can be flat or raised, smooth or rough, and some have hair growing from them. Moles are usually circular or oval in shape with a smooth edge.
Moles can change in number and appearance. Some moles fade away or fall off over time, often without you realising. They sometimes respond to hormonal changes, such as during:
- pregnancy, when they may get slightly darker
- the teenage years: when they increase in number
- older age: some even disappear from 40 to 50 years of age onwards
When do moles develop?
Some moles are present at birth. These are called congenital melanonaevi naevi. However, most moles develop during the first 30 years of life. These are called acquired melanocytic naevi. People with fair skin often develop more moles than people with darker skin.
Most moles have a genetic cause and are inherited. This is often the case with people who have a lot of moles. Where you were brought up may also make a difference. For example, if you have been in the sun a lot for many years you may have an increased number of small moles.
People who spend a considerable amount of time in the sun often develop brown marks on their skin, especially the face and arms. These tend to be sun spots or solar lentigines and appear later on in life. Severe sunburns on the shoulders, for example, may also cause some sun spots which are not moles.
See the topic about Sunburn for more information.
Malignant melanoma
Most moles are harmless, but in a few rare cases they can develop into malignant melanoma, which is an aggressive form of skin cancer.
Malignant melanoma is the most serious type of skin cancer. The cause of melanoma is complex and is usually explained by a mix of genetic factors and the environment, mainly exposure to the sun. However, many melanomas are not caused by excessive sunbathing and may occur on parts of the body that have not been exposed to much sun
Malignant melanoma can appear anywhere on the body. It may be a dark, fast-growing spot where there was not one already, or a mole you already have that changes size, shape or colour, and bleeds, itches or reddens. However, the bleeding, crusting and itching are late signs and ideally melanoma should be diagnosed earlier. Itching is also not a very specific sign, as benign (non-cancerous) moles may itch occasionally.
For more information on melanoma, See the topic: Malignant melanoma
Harmless moles
You should check all your moles every few months for any changes. A change in a mole may occur in weeks but in some moles it may occur in months. See Moles - prevention for information and advice about checking your moles and the changes to look out for. If there are no changes it is not a melanoma, as a melanoma will change with time.
Types of moles
There are several different types of moles - for example:
- junctional melanocytic naevi: these are usually brown, round and flat
- dermal melanocytic naevi: these are usually raised, light- or skin-coloured and are sometimes hairy
- compound melanocytic naevi: these are usually raised above the skin, light brown and sometimes hairy
- halo naevi: this type of mole is surrounded by a white ring where the skin has lost its colour; the skin regains its colour when the mole at the centre of the halo gradually fades away
- dysplastic or atypical naevi (also known as Clark naevi): an unusual looking and slightly larger mole (above 5mm or 0.2 inches), they can be a range of colours and flat or bumpy; they may have irregular edges and do not change over time
Seborrhoeic keratoses are skin blemishes that can mimic moles. They are benign (non-cancerous) and are common in older people. They differ from moles and look like raised warts. Seborrhoeic keratoses can be skin-coloured, black, dirty-yellowish or a grey-brown colour. They can crumble away from the skin and you usually have several, especially on the chest and tummy.
Freckles are small, flat brown marks that often appear on the face or areas that are exposed to the sun. They are caused by an increased amount of melanin, the pigment that gives your skin colour. They are not moles, which are a group of melanocyte cells.
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Diagnosis
It is important to check your moles regularly and be aware of any changes in their colour, shape or size. Most changes are harmless and are due to a benign (non-cancerous) increase of pigment cells in the skin. However, you should see your GP if a mole looks unusual.
See Moles - prevention for information about checking your moles and the changes to look out for.
Visiting your GP
Your GP will ask you about recent changes that have happened to the mole and when the changes started. They may also ask you about your family history to find out how likely you are to be at risk of melanoma (a type of skin cancer).
Diagnostic checklist
Your GP will assess your mole using a checklist that consists of seven points from the National Institute for Health and Clinical Excellence (NICE). These are:
- whether the mole has changed size
- whether the mole is an irregular shape
- whether the mole is an irregular colour
- whether the mole measures 7mm (0.28 inches) or more across
- whether the mole is inflamed (red and swollen)
- whether the mole is oozing (leaking fluid)
- whether the mole has changed in sensation, for example, causing itching or pain
If there are only mild changes, your GP will probably take a clinical photograph of the mole and may measure it with a ruler. You may be asked to return in around eight weeks. Your GP will then compare your mole with the photograph and the measurements they took at your last visit to determine whether there have been any further changes.
If the mole shows signs of turning malignant (cancerous), your GP may refer you to a specialist under the two-week rule, so you should not wait more than 14 days to be seen. This might be with a:
- dermatologist (a specialist in conditions that affect the skin)
- plastic surgeon
Seeing a specialist
The specialist will examine you and either reassure you that the mole is not cancerous or they will cut the mole out. This is known as an excision biopsy. The entire mole should always be removed in one go unless it is large or in a difficult location.
NICE do not recommend that GPs perform biopsies on suspicious looking moles.
If the specialist decides to remove your mole, the sample is then sent to a laboratory to be looked at under a microscope for signs of cell change.
If the mole is a suspected melanoma, your specialist will discucss this with you. Further tests may be necessary to check that the cancer has not spread. A multidisciplinary team (MDT) will probably take over your treatment. An MDT is a team of healthcare professionals with expertise in a variety of areas who work together to treat cancer. It may include:
- dermatologists
- plastic surgeons
- oncologists (specialists in cancer)
- pathologists (specialists in diagnosing diseases)
- skin cancer nurse specialists
See the Health topic about Skin cancer (malignant melanoma) - treatment for more information.
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Treatment
Treating cancerous or unsightly moles
Most moles do not require any treatment. However, a mole may be removed if:
- it could be a melanoma (a type of skin cancer)
- it is a nuisance; for example, if it gets caught on clothing or makes shaving difficult
Melanoma
If melanoma is found early on, it can normally be removed with a simple surgical technique. This is because at this stage the melanoma is still thin and has not yet grown downwards from the skin surface or spread to other parts of the body.
If melanoma is not found early, it will still be removed as a whole, with some normal skin around it also removed as a safety margin. The cancer cells from the melanoma may have spread through the bloodstream or lymphatic system (network of channels and glands) and form tumours (cancerous growths)elsewhere, so you may also need further treatment.
See the Health topic about Skin cancer (malignant melanoma) - treatment for more information.
How a mole is removed
Before a mole is removed, the area of skin is cleaned, and numbed with a local anaesthetic (painkilling medication). The surgeon uses a scalpel (sharp medical knife) to cut the mole out. It will then be sent to a laboratory to be checked for signs of melanoma.
Most of the time you will have stitches to close the wound or it may be closed by burning the area (cautery).
If the mole is removed as a whole because it is suspected to be a melanoma, then stitches will be used. The wound is covered with a sterile (clean) dressing, and the surgeon or nurse will tell you how to look after it until it ishealed.
Wide local excision
If your mole is found to be a melanoma, you may need to have some more of the surrounding skin removed. This is known as a wide local excision and it is carried out to ensure that all of the abnormal cells have been.
Depending on how much skin tissue needs to be removed, you will have a local anaesthetic, or very rarely a general anaesthetic (where you are unconscious). The surgeon will remove more skin and tissue from around and underneath the mole and will use stitches to close the wound. The skin may feel a little bit tight afterwards but will relax and stretch after a while.
Nuisance moles and unsightly moles
If you are having a mole removed because it looks unsightly or it is a nuisance, for example, because it catches on your clothes, less tissue will need to be removed. Your surgeon may just shave the mole off so that it is level with your skin. This is known as a shave excision. The wound may be cauterised to close it.
Removing a mole for cosmetic reasons
Moles are sometimes removed for cosmetic reasons even if they are harmless. For example, if a person has a mole they think is large and unsightly and is affecting their self-esteem and confidence.
You will usually have to pay for this type of treatment, and it is often carried out at a private clinic. Ask your GP for advice about where to get treatment.
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Prevention
There is nothing you can do to prevent moles from forming, but you can take measures to lower the risk of a mole becoming cancerous (malignant melanoma).
Skin cancer is the most common types of cancer in the UK, and the number of people developing skin cancer is increasing. According to Cancer Research UK, there are over 10,600 people diagnosed with melanoma (a type of skin cancer) in the UK every year. This is why it is so important to be aware of your skin and regularly check your moles - both old and new.
Check your moles every couple of months for any changes. Look out for the following:
- Moles that get a lot bigger (most moles are no bigger than the width of a pencil)
- Moles with uneven colouring – most moles only have one or two colours but melanomas have lots of different shades
- Moles with an uneven or ragged edge – moles are usually circular or oval with a smooth border
- Bleeding, itching, red, inflamed (swollen) or crusty moles (that haven’t been picked or caught on something) seek medical attention
- The appearance of a new mole that looks irregular or unusual. It’s normal to develop new moles as you get older but you should get them checked out by your GP if the colours are patchy or the edges are uneven
- A sore lump or blemish that does not have an obvious cause and lasts for more than a few weeks
- Patches of skin that are flaky, itchy, tender, oozing, bleeding or red that do not have an obvious cause, such as eczema (a condition that causes dry, flaky skin).
Visit your GP immediately if you notice anything unusual about a mole or if you have a mole that is getting bigger.
Sun safety
The best prevention against skin cancer is to be careful in the sun and limit the amount of time you spend in the sun.
Do not be fooled into thinking you’ll only burn if you sunbathe. Travelling in a car, gardening and playing sport outdoors all expose you to the sun. You can burn when the sun is behind the clouds, on a sunny day.
Ultraviolet (UV) radiation from the sun (which burns your skin) is most intense:
- in the middle of the day between April and September
- at high altitudes (such as on skiing holidays)
- the closer you are to the equator, such as in parts of Africa
Follow these guidelines to stay safe:
- stay in the shade when the sun is at its strongest (between 11am and 3pm)
- keep babies and young children out of the sun – use a high factor sunscreen (minimum SPF15) and dress them in loose clothing to protect their delicate skin
- cover up with clothes, a wide-brimmed hat and sunglasses
- use a high-factor sunscreen (minimum SPF15) and re-apply it regularly, particularly after swimming
- avoid using sunlamps or sunbeds as they give out UV rays.
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Risks
Most types of skin cancer are caused by exposure to the sun but having lots of moles or unusual moles can also increase your risk of getting skin cancer.
Dysplastic or atypical naevi
Dysplastic or atypical naevi (also called Clark naevi) are abnormal moles that are usually flat and fairly large. They tend to have irregular borders and uneven colour, sometimes showing lots of different shades. Having lots of dysplastic or atypical naevi may increase your risk of developing melanoma (a type of skin cancer).
Numerous moles
Your risk of developing melanoma is also increased if you have a lot of moles; usually more than about 50. If you have a lot of moles, you should be very careful in the sun and check your moles regularly for any sign of change (see Moles - prevention). This is particularly important if there is a history of melanoma in your family.
Other risk factors
Other risk factors for melanoma include:
- Having a lot of freckles
- Having very pale skin
- Being female (melanoma is more common in women than men)
- Getting badly sunburnt on a lot of occasions
- Spending a lot of time sunbathing
- Having a previous melanoma that was diagnosed and removed in the early stages
See the Health topic about Skin cancer (malignant melanoma) - causes for more information and advice.
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