There are several skin lesions that are very common and benign (non-cancerous). These conditions include moles, freckles, skin tags, benign lentigines, and seborrheic keratoses.
Moles and Your Skin
Most moles appear in early childhood and during the first 25 years of a person's 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 color. Sometimes, hairs develop in 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 color. Moles may darken after exposure to the sun, during the teen years, and during pregnancy.
Types of Moles
Congenital nevi are moles that are present at birth. Congenital nevi occur in about one in 100 people. These moles are slightly more likely to develop into melanoma (cancer) than are moles that appear after birth. A mole or freckle should be checked if it has a diameter of more than a pencil eraser or any characteristics of the ABCDEs of melanoma (see below).
Dysplastic nevi are moles that are generally larger than average (larger than a pencil eraser) and irregular in shape. They tend to have uneven color with dark brown centers and lighter, uneven edges. These nevi are somewhat more likely to become melanoma. In fact, people who have 10 or more dysplastic nevi have a 12 times higher chance of developing melanoma, a serious form of skin cancer. Any changes in a mole should be checked by a dermatologist to evaluate for skin cancer.
How Do I Know if a Mole Is Cancer?
The vast majority of moles are not dangerous. Moles that are more likely to be cancer are those that look different than other existing moles or those that first appear after age 25. If you notice changes in a mole's color, height, size, or shape, you should have a dermatologist (skin doctor) evaluate it. You also should have moles checked if they bleed, ooze, itch, or become tender or painful.
Examine your skin with a mirror or ask someone to help you. Pay special attention to areas of the skin that are often exposed to the sun, such as the hands, arms, chest, neck, face, ears, legs, and back.
If a mole does 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 dermatologist.
The following ABCDEs are important characteristics to consider when examining moles. If a mole displays any of the signs listed below, have it checked immediately by a dermatologist. It could be cancerous.
- Asymmetry. One half of the mole does not match the other half.
- Border. The border or edges of the mole are ragged, blurred, or irregular.
- Color. The color of the mole is not the same throughout or has shades of tan, brown, black, blue, white, or red.
- Diameter. The diameter of a mole is larger than the eraser of a pencil.
- Evolution. The mole is changing in size, shape, or color.
Melanoma is a form of skin cancer. The most common location for melanoma in men is the chest and back and in women, it is the lower leg. Melanoma is the most common cancer in young women.
How Are Moles Treated?
If a dermatologist believes a mole needs to be evaluated further, they will do a biopsy by shaving or cutting out the entire spot so that it can be evaluated under the microscope. This is a simple procedure. (If the dermatologist thinks the mole might be cancerous, cutting through the mole will not cause the cancer to spread.)
If the mole is found to be cancerous, the dermatologist will cut out the entire mole or scar from the biopsy site by cutting out the entire area and a rim of normal skin around it, and stitching the wound closed.
A skin tag is a small flap of tissue that hangs off the skin by a connecting stalk. Skin tags are not dangerous. They are usually found on the neck, chest, back, armpits, under the breasts, or in the groin area. Skin tags appear most often in women, especially with weight gain, and in elderly people.
Skin tags usually don't cause any pain. However, they can become irritated if anything, such as clothing, jewelry, or skin rubs against them.
How Are Skin Tags Treated?
Your dermatologist can remove a skin tag by cutting it off with a scalpel or scissors, with cryosurgery (freezing it off), or with electrosurgery (burning it off with an electric current).
Lentigo and Your Skin
A lentigo (plural: lentigines) is a spot on the skin that is darker (usually brown) than the surrounding skin. Lentigines are more common among whites, especially those with fair skin.
What Causes Lentigines?
Exposure to the sun seems to be the major cause of lentigines. Lentigines most often appear on parts of the body that get the most sun, including the face and hands. Some lentigines may be caused by genetics (family history) or by medical procedures such as radiation therapy.
How Are Lentigines Treated?
There are several methods for treating lentigines:
- Cryosurgery (freezing it off)
- Laser surgery
- Skin creams such as retinoids and bleaching agents
Can Lentigines Be Prevented?
The best way to prevent lentigines is to stay out of the sun as much as possible, especially between the hours of 10 a.m. and 2 p.m. Use a broad-spectrum sunscreen with an SPF of 30 or higher when outdoors, and wear protective clothing, such as long-sleeved shirts, pants, and a wide-brimmed hat. Avoid using tanning beds.
Freckles and Your Skin
Freckles are small brown spots usually found on the face, neck, chest, and arms. Freckles are extremely common and are not a health threat. They are more often seen in the summer, especially among lighter-skinned people and people with light or red hair.
What Causes Freckles?
Causes of freckles include genetics and exposure to the sun.
Do Freckles Need to Be Treated?
Since freckles are almost always harmless, there is no need to treat them. As with many skin conditions, it's best to avoid the sun as much as possible, or use a broad-spectrum sunscreen with SPF 30. This is especially important because people who freckle easily (for example, lighter-skinned people) are more likely to develop skin cancer.
If you feel that your freckles are a problem or you don't like the way they look, you can cover them up with makeup or consider certain types of laser treatment, liquid nitrogen treatment or chemical peels.
Seborrheic Keratoses and Your Skin
Seborrheic keratoses are brown or black growths usually found on the chest and back, as well as on the head. They originate from cells called keratinocytes. As they develop, seborrheic keratoses take on a warty appearance. They do not normally lead to skin cancer.
What Causes Seborrheic Keratoses?
The cause of seborrheic keratoses is unknown. They are seen more often as people get older.
How Are Seborrheic Keratoses Treated?
Seborrheic keratoses are harmless and are not contagious. Therefore, they don't need to be treated.
If you decide to have seborrheic keratoses removed because you don't like the way they look, or because they are chronically irritated by clothing, methods for removing them include cutting them off, cryosurgery, and electrosurgery.