3 Things to Know About Melanoma

If you see something, say something.

That is the key takeaway Jeffrey Cohen, MD, MPH, a Yale Medicine dermatologist, wants people to remember if they notice a suspicious spot on their body that looks like melanoma, the most dangerous type of skin cancer.

Although it is not the most common form of skin cancer, melanoma is responsible for the most cancer deaths. Melanoma begins in pigment-producing cells, called melanocytes; the primary risk factor is exposure to ultraviolet (UV) light, mainly from the sun and tanning beds. Melanoma can grow quickly and spread to other parts of the body if not caught early.

Regular skin checks and prompt attention to any changing, new, or unusual spots are needed for early detection. “The majority of first-time cases of melanoma are found by patients themselves,” Dr. Cohen notes, stressing the importance of self exams to assess moles—common skin growths that typically appear as small, dark spots.

The average person has about 100 moles, Dr. Cohen says, adding that most develop by age 30, but new ones can arise at any age. “In general, moles should stay the same size, shape, and color, and any changes should be checked by a doctor,” he says. “However, the vast majority of melanomas do not develop from an existing mole, but arise in an area where there was never a mole before.”

Below, Dr. Cohen offers tips on what to look out for—plus where melanoma can appear (hint: not just sun-exposed parts of the body) and how to reduce your risk.

The ABCDEs is a mnemonic way for remembering five key points when considering worrisome spots on your body. If you meet any or all of the following criteria, you should have your skin examined by a medical professional.

A: Asymmetry. In general, a mole should be symmetrical, or have one side match the other in terms of size, shape, and color.

B: Border. You should be able to take a pen and easily draw a circle around the mole. It shouldn’t have borders that are jagged or blurred.

C: Color. Moles should be uniform in color, and it is concerning if one mole has multiple colors, such as brown, red, and black.

D: Diameter. It should not be larger than the tip of an eraser.

E: Evolution. If the mole is changing and looks different one month to the next, that is a reason for concern.

“Of course, having a spot on the body that fits any of this criteria doesn’t necessarily mean it’s melanoma, but they are signs that mean you should have a medical professional take a look,” Dr. Cohen says.

For a guide on how to conduct a self-exam, Dr. Cohen recommends visiting the American Academy of Dermatology website and doing an exam once a month.

Dr. Cohen also suggests patients look out for what he calls “ugly ducklings.”

“This means a lesion or mole on the skin that doesn’t look like anything else you have,” he explains. “If you could look at all the spots on your body and group them together in ways that many look similar but you have this one that doesn’t look like anything else on your skin, that is something you should have a dermatologist or other medical professional evaluate.”

While melanoma often appears in areas that are typically exposed to UV light, including face, neck, arms, legs, and back, it can also develop in unexpected places, such as the bottom of the foot, under nails, on palms, in the back of the eye, and even in the mouth.

“The vast majority of melanomas originate from the skin, but you can get melanoma in areas that aren’t exposed to the sun,” Dr. Cohen says. “So you don’t want to neglect areas when you are checking. One of the reasons why outcomes for melanoma on the feet are not as favorable for other parts of the body is because not everybody looks there, and it can spread if it’s caught too late.”

Individuals who are at higher risk for melanoma should consider speaking with their doctor about scheduling regular skin exams with a dermatologist. Factors that increase the risk include a history of blistering or peeling sunburns, tanning bed use, a family history of melanoma, certain hereditary conditions (such as familial atypical multiple mole melanoma syndrome), and having a weakened immune system—including organ transplant recipients, people with certain autoimmune disorders, or those taking specific medications.

Regardless of your risk factor, Dr. Cohen strongly urges everyone to wear broad-spectrum sunscreen, which protects against UVA and UVB rays that cause aging and burning, respectively.

“There’s no such thing as a base tan,” he adds. “Ideally, you don’t want your skin color to change at all. And any sunburn that blisters or peels raises your risk.”