Moles

A mole (or melanocytic naevus) is an abnormal collection of pigment cells present within the skin. These cells are known as melanocytes. Moles are extremely common. Most people are born with a few moles and develop others during their lives.

 

Moles are small dark marks on the skin. They are a collection of skin pigment cells called melanocytes.

Moles are usually brownish, although some may be darker or skin-coloured. They 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.

They can start to look different over time and sometimes respond to hormonal changes, such as during pregnancy, adolescence and the menopause. Some moles even disappear over time or fall off, often without you realising.

Mole

When do moles develop?

Some moles are present at birth. These are called congenital melanocytic naevi. However, most moles develop during the first 20 years of life (and sometimes into the 30s and 40s).

Halo naevi are moles that are sometimes seen in children and young adults. They are surrounded by a white ring, where the skin has lost its colour. The skin regains its colour when the mole in the centre of the halo disappears, which can take a few years.

Seborrhoeic keratoses are skin blemishes that can mimic moles. They are benign (not cancerous) and are common in older people. They can be skin-coloured, brown or black, and look like raised warts.

In general, moles often develop if you spend a lot of time in the sun, and tend to appear on parts of the body that catch the most sunlight, such as your face   

Other Types of Moles

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.

 

Dysplastic naevus syndrome

 

Some large moles have an irregular outline and an indistinct border. These carry an increased risk of malignancy and tend to occur in families who have a history of malignant melanoma. Patients with such moles need to have them examined regularly and compared with clinical photographs.


Halo naevi

Occasionally the skin surrounding a small mole becomes lighter and the central mole becomes pale. Most halo naevi are benign. But some people may have an increased risk of developing the skin disorder, vitiligo. Patients with malignant melanoma may, very rarely, develop halo naevi.

Blue naevus

This deep-seated mole appears blue. It is very common in some West Indian infants but is only rarely of any significance.

Juvenile melanoma (Spitz naevus)

In this condition, the pigment cells form a benign tumour, which is usually a pink-brown colour. Although similar to melanoma, the outlook following treatment is good.

Complications of Moles

Certain types of moles are more likely to develop into skin 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