Moles are small brown spots which develop on the skin and are usually harmless although they have the potential to turn into a form of skin cancer called malignant melanoma.

Malignant melanoma is discussed further in our melanoma section.

Most people have moles and the amount you have depends upon genetics and the type of skin you have. If you have fair skin then you will have moles than someone with a darker skin.

The amount of moles you have changes at various stages in your life. They can fade or completely disappear for no obvious reason or change colour. These changes occur during puberty, pregnancy and middle age – often when there are fluctuations in hormone levels, particularly in women.

Causes of moles

Most moles appear at birth. These are known as ‘congenital melanocytic naevi’ and have a light brown colour. But most people develop moles during childhood and early adulthood. These are known as ‘acquired melanocytic naevi’.

Moles are also inherited. If either or both your parents have a large number of moles then you will inherit this tendency.

Another factor is climate. If you were brought up in a hot climate and spent much of your time outdoors then you will have more moles than someone in a cooler climate.

Is there more than one type of mole? The answer to that is yes. Read on…

Different types of moles

We have already mentioned about moles which are present at birth and those which appear in youth and adulthood. But there are several other types as well which include:

  • Compound melanocytic naevi: small light brown moles which are raised above the surface of the skin and may have a hair or two growing from them.
  • Junctional melanocytic naevi: common round, flat, brown coloured moles.
  • Dermal melanocytic naevi: light coloured moles which are raised above the skin and may contain a hair or several hairs.
  • Halo naevi: a type of mole which is encircled by a white ring
  • Atypical naevi: moles which do not fit into any of these categories. They come in a range of shapes and sizes and different colours.

There are also moles or benign growths called seborrheic keratosis which are similar in appearance to warts and mainly affect older people.

And finally, there are freckles which are small round brown spots that are caused by an increase in the amount of melanin in the skin. These develop on parts of the body which are exposed to the sun, for example the face and arms. These are NOT moles.

Mole check

The majority of moles are harmless but there is a small risk of one of these becoming cancerous, leading to a condition called malignant melanoma. But this is rare.

However it is a good idea to get into a routine of checking your moles every month or so to see if there are any changes. A mole can change in a few weeks or over several months. But don’t assume that any changes to a mole are cancer as there may be other reasons for this.

But visit your GP if you notice any changes to a mole which include bleeding, increased size, two tone appearance, irregular shape and/or colour, inflamed, itching and painful and if it oozes fluid.

It is better to be safe than sorry. Ask your GP for advice even if it turns out to be nothing. Even if you are unsure about whether there has been a change in a mole.

Your GP will examine the mole and refer you to a dermatologist for further investigation.

If your mole is proven to be cancerous, i.e. melanoma, then a treatment plan will be devised following consultation between you and a healthcare team. Find out more about the treatment for skin cancer in our melanoma section.