Moles, also known as melanocytic nevus (plural: nevi) are small lesions in the skin. They are a collection of melanocytes. Melanocytes are melanin-producing cells. Melanin is a pigment which gives our skin its color. Moles are usually brownish, but some may be much darker, while others are skin-colored. They can be rough, flat, raised, and have hair coming out of them. They are generally round or oval, and have a smooth edge.
Moles can change in appearance and numbers. Sometimes they eventually fade away or drop off. Some moles respond to changes in hormone levels, as may occur during pregnancy, adolescence and older age. During our teen years they usually grow in number, get darker during pregnancy and gradually fade away when we are older.
The majority of moles appear during the first 20 to 30 years of a person's life, however, some may be present when the baby is born. Congenital Melanocytic nevi are present at birth, any moles appearing after birth are melanocytic nevi. Dark skinned people generally have fewer moles than those with fair skin.
Most moles are inherited. People brought up in sunny places tend to have more moles than others with the same type of skin who were raised in areas with comparatively little sun exposure.
Sun spots, which may be caused by severe sunburn, are not moles.
If you have moles, you should check them regularly for changes in texture and/or appearance.
Types of Moles
An example of what was considered a normal mole. In this case the edges were deemed to be even, not ragged and not notched. Part of the ABCDs for detection of melanoma. Source: National Cancer Institute
- Junctional melanocytic nevi - usually round, flat and brown.
- Dermal melanocytic nevi - usually raised, sometimes has hair, skin colored or light brown.
- Halo nevi - the skin around it has lost its color, so it has a white ring around it, hence the name. When the mole eventually fades away, the skin regains its color.
- Dysplastic nevi - also known as atypical nevi or Clark nevi - can be flat or bumpy, is large, the edges may be irregular and do not change over time. It is an unusual looking mole.
Older people tend to have seborrheic keratoses. These are not moles; they may look like them, but they are blemishes. They look like raised warts. They can be gray, brown, yellowish or black. They are more commonly found on the tummy and chest.
Freckles are not moles.
Symptoms of moles
A symptom is something the patient feels and reports, such as pain, while a sign is something other people can also identify, such as a rash.
In general, moles are brown; however, they can come in a variety of sizes, shapes and colors:
- Shape - they can be oval and round
- Color - they are usually medium-to dark brown, reddish brown, or flesh colored
- Size - moles can vary enormously in size. They can cover an entire arm, or be as small as a pinhead. Typically, they are less than 6 mm (1/4 inch) long.
The average human has from 10 to 14 moles. They can develop on the scalp, under the nails, armpits, virtually anywhere on the body. The total number of moles a person can have usually varies during their lifetime.
A mole's surface can be raised, wrinkled, flat or smooth. They may start out with one color and be flat, and then become slightly raised, and the color may lighten. Some may develop a small stalk, and gradually wear off. Often, moles will disappear completely.
Most moles appear during early life, up to the age of about 20 years, however, they can continue appearing until middle age.
Moles that emerge after the age of 20 should be shown to a doctor. You should also see your doctor if a mole itches, has a burning sensation, is painful, bleeds or oozes, is crusty or scaly, or suddenly changes in color, elevation, size or shape.
While people with more than 50 moles may be at higher risk of developing melanoma, people who have fewer moles may be at greater risk of developing more aggressive melanoma.
The number of moles on one's right arm could be used to predict the risk of melanoma - the deadliest form of skin cancer - according to a new study by researchers from King's College London in the UK.
Possible complications of moles
Some moles can become cancerous. Especially:
- Congenital nevi - these are large moles that people are born with. They raise the individual's risk of developing malignant melanoma, an aggressive and potentially fatal type of skin cancer.
- Moles that appear in families - atypical (dysplastic) nevi are larger than normal and are usually hereditary. Individuals with dysplastic nevi have a higher risk of developing malignant melanoma than other individuals.
- Many moles - people with numerous moles run a greater risk of developing malignant melanoma.
On the next page we look at how to diagnose cancerous moles, treatments for moles and how to protect yourself from skin cancer.