Moles are made up of localised collections of melanocytes in the skin. Melanocytes are the cells responsible for producing melanin, a black pigment found in our skin, hair and in the eye.

Most moles appear in early childhood, and there may be a sharp increase in the numbers during adolescence. Genetic factors are important, some people have more moles than others. Excessive exposure to the sun in childhood may also be responsible in part, for the number present in the skin of an individual. Some people are born with a lot of large, dark moles (dysplastic naevus syndrome) and they should probably be monitored by a dermatologist.

The majority of moles are not a problem, although they can give rise to a lot of anxiety due to the increased awareness of skin cancer. Recognising the significance of change in a mole can lead to the early detection of malignant melanoma (the most aggressive form of skin cancer), which in turn can make the difference between success and failure of treatment.

Features to look out for are

  • Increase in size
  • A change in the colour, most significant if it becomes darker
  • Irregularity of the pigment within the mole
  • A change in the shape, particularly if the outline becomes irregular or more raised
  • Itching
  • Crusting (or leaking of fluid) on the surface of the mole
  • Bleeding (which is clearly not due to trauma)
Very rarely you can get amelanocytic melanomas these are melanomas with no pigment. Any spot on your skin which grows in size, spontaneously ulcerates, bleeds or refuses to heal should be examined by a doctor.

Remember protection of your skin from excessive sun is very important, see our sunshine advice leaflet for more information.

Further information

Sunshine advice page

This article published on
08 February 2006

Next review date 2/1/2013


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Skin and hair
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