Moles are growths on the skin that are usually brown or black. Moles can appear anywhere on the skin, alone or in groups.
Most moles appear in early childhood and during the first 20 years of a person's life. Some moles may not appear until later in life. It is normal to have between 10-40 moles by adulthood.
As the years pass, moles usually change slowly, becoming raised and/or changing colour. Often, hairs develop on the mole. Some moles may not change at all, while others may slowly disappear over time.
What causes a mole?
Moles occur when cells in the skin grow in a cluster instead of being spread throughout the skin. These cells are called melanocytes, and they make the pigment that gives skin its natural colour. Moles may darken after exposure to the sun, during the teenage years, and during pregnancy.
Types of moles
Congenital naevi are moles that appear at birth. Congenital naevi occur in about one in 100 people. These moles may be more likely to develop into melanoma ( skin cancer) than moles that appear after birth. A mole or freckle should be checked if it has a diameter of more than 6mm or any of the other characteristics of the ABCDEs of melanoma (below).
Dysplastic naevi are moles that are larger than average and irregular in shape. They tend to have uneven colour with dark brown centres and lighter, uneven edges. These moles tend to be hereditary (passed on from parent to child through genes). People with dysplastic naevi may have more than 100 moles and have a greater chance of developing melanoma, a potentially fatal form of skin cancer. Any changes in a mole should be checked by a doctor to detect skin cancer.
How do I know if a mole is cancerous?
Most moles are not dangerous. The only moles that are of medical concern are those that look different from other existing moles or those that first appear after the age of 20. If you notice changes in a mole's colour, height, size or shape, you should seek medical advice to evaluate it. You should also have moles checked if they bleed, ooze, itch, appear scaly or become tender or painful.
Examine your skin with a mirror or ask someone to help you. Pay special attention to areas of your skin that are often exposed to the sun, such as the hands, arms, chest, neck, face and ears.
If your moles do not change over time, there is little reason for concern. If you see any signs of change in an existing mole, if you have a new mole, or if you want a mole to be removed for cosmetic reasons, talk to your doctor or dermatologist.
To provide even greater transparency and choice, we are working on a number of other cookie-related enhancements. More information