A nevus, also known as a birthmark, is a skin malformation that typically presents itself as a discolored or pigmented area on the skin. These markings can be present at birth or develop later in life. Nevus birthmarks are the result of either abnormal pigmentation or dilated capillaries.
Nevus classifications can be categorized into various types, as follows:
Nevus classification can be based on the timing of their appearance on the body, as follows:
Nevi can be present at birth (congenital nevi) or develop later in life (acquired nevi).
Another way to classify nevi is based on their color, as follows:
- Pigmented nevus: These birthmarks are caused by an excess or abnormal distribution of melanocytes, the cells responsible for producing melanin. Pigmented nevi can appear as flat or raised spots on the skin, varying in color from light brown to black. Examples include café-au-lait spots, Mongolian spots, and congenital melanocytic nevi.
- Vascular nevus: These birthmarks are caused by dilated or malformed capillaries (tiny blood vessels) near the surface of the skin. They can appear as flat or raised areas, often with a reddish, pink, or purple hue. Examples include port-wine stains, hemangiomas, and salmon patches.
Nevus classification can also be determined by the cause and components that form the nevus, as follows:
- Congenital melanocytic nevi (CMNs): CMNs are large, dark birthmarks that are present at birth. They are most common on the trunk and limbs, but can occur anywhere on the body. CMNs are more common in people with fair skin.
- Melanocytic nevi: Melanocytic nevi are small, brown or black spots that develop on the skin during childhood or adolescence. They are the most common type of nevus.
- Vascular nevi: Vascular nevi are birthmarks that are caused by dilated capillaries. They can be red, pink, or purple in color. Vascular nevi are most common on the face, neck, and chest.
Most nevi are harmless and do not require treatment. However, some nevi, such as CMNs, are at increased risk of developing skin cancer. If you have a nevus that changes in size, shape, or color, or if it starts to bleed or itch, see a doctor right away.
Here are some additional information about nevi that may be helpful for beauty professionals and estheticians:
- Nevi are most common in people with fair skin.
- Nevi are more common in people with a family history of skin cancer.
- Nevi are more common in people who have been exposed to a lot of sun.
- Nevi can be removed by a doctor, but this is usually not necessary.
The terms “nevus” and “mole” are often used interchangeably, as both refer to a benign skin growth caused by the clustering of melanocytes, the pigment-producing cells in the skin. However, there are some subtle differences between the two:
- Terminology: “Nevus” is the medical term for a mole, and it is often used by healthcare professionals when discussing pigmented skin growths. “Mole” is the more common term used by the general public.
- Variety: While “mole” typically refers to a pigmented skin growth, “nevus” can encompass a broader range of skin growths or birthmarks, including both pigmented and vascular types. For example, a vascular nevus, such as a port-wine stain or hemangioma, is caused by dilated or malformed blood vessels, whereas a pigmented nevus is caused by melanocytes.