The ABCDEs Skin Cancer Assessment

Did you know that skin cancer is the most common cancer in the United States?

Melanoma affects over 1 million Americans, and its rates have risen significantly in the past 30 years, according to the American Academy of Dermatology (AAD). One in five Americans develops skin cancer, and one person dies every hour from melanoma, the deadliest form of the disease.

Skin cancers, including melanoma, are highly treatable when detected early, and learning how to perform a skin self-exam could save your life. Learn how to do the ABCDE skin assessment and know if your moles are showing signs of possible skin cancer.

What is a Skin Self-Exam?

It’s essential to check your skin regularly – and a self-exam is the perfect way to check for any unusual lumps, bumps, rashes or abnormalities.

While doing a skin self-exam, look at all the spots you see on your body, including moles, freckles and age spots. You can get skin cancer anywhere, including the palms of your hands, soles of your feet, mouth, eyes, genitalia and buttocks. (Learn about common places skin cancer hides.)

In darker skin, it is more likely to develop in areas that aren’t exposed to the sun, such as under or around your nails, palms or soles.

Tips for doing a skin cancer self-exam

• Use a full-length mirror to examine your entire body, front and back.
• Raise your arms to look at your left and right sides.
• Bend your elbows and carefully check your forearms, underarms and palms.
• Check the back of your legs and feet, between your toes and on the soles of your feet.
• When nail polish is removed, check your fingernails and toenails.
• Use a hand mirror to check the back of your neck, scalp, hair, back and buttocks.

If you need help, ask a partner to check hard-to-see areas. 

You can download a mole body map from the American Academy of Dermatology to track any changes in your moles.

What Is ACBDE Rule For Melanoma?

Even with using sunscreen and wearing protective clothing, skin cancer lesions can still develop. Experts suggest using the ABCDE rule to keep an eye on your skin.

"ABCDE is mnemonic that we use to make it simple to look for changes in freckles and moles," said Juliana Meyer, MD, melanoma surgeon with Franciscan Health Indianapolis. "Freckles and moles are basically the same thing. Everyone has what we call pigmented lesions or spots on their skin, some more than others. And we look for patterns in these. Do the moles have changes?"

Dr. Meyer illustrates what to look for with moles and freckles when doing self-checks as the "ABCDEs" of skin cancer detection. We'll break these down more, below.

• A—Asymmetry. Is one side changing while the other stays the same? Does one half of the spot look different from the other?
• B—Border. Is the border irregular or rough at the edges? Does the border look irregular, scalloped or poorly defined?
• C—Color. Is one part of the mole a different color than the rest? Are there parts of the mole that are different from the next with shades of tan, brown or black or areas of white, red or blue?
• D—Diameter. Melanomas are usually the size of a pencil eraser or larger, when diagnosed. But they can be smaller. Any lesion that is 0.5 centimeters or larger should be looked at.
• E—Evolution. Watch for any signs of a mole changing over time. Are any spots looking different from the rest or are changing in size, shape or color?

See a medical professional if you have any of these signs or notice an existing mole start to change in any way.

A: Asymmetry

Most melanomas are asymmetrical, meaning that two halves of the mole or lesion do not match. If you draw a line down the middle of a melanoma spot or mole, one half won't typically match the other. Instead of a round or oval shape, it may appear oddly shaped. “Is one side of a mole or freckle changing, and the other is staying the same?” Dr. Meyer said.

B: Border

Borders around melanoma tend to be uneven and may have scalloped or notched edges.

Regular moles tend to have smoother, more even borders.

C: Color

Multiple colors or uneven colors are a warning sign of possible skin cancer. While benign moles are usually a single shade of brown, a melanoma may have different shades of brown, tan or black. As it grows, the colors red, white, pink, grey or blue may also appear.

In some cases, part of the mole may have a different color than the other, Dr. Meyer said.

D: Diameter

A change or increase in size in a mole or lesion can be a symptoms of skin cancer.

"We see melanomas of all shapes and sizes, but we do know that if there's a lesion that's changing rapidly in terms of color and size, diameter, that's where we want to pay attention," Dr. Meyer said. "That's where the D comes in."

"It used to be that anything a centimeter or greater would trigger it. But now, we do think that probably closer to 0.5 centimeters, which is 5 millimeters or greater, we need to just kind of keep an eye on it."

An easy way to picture 0.5 cm is the approximate size of the eraser on a pencil.

E: Evolution

Change isn't good when it comes to moles. Any change in size, shape, color or elevation of a spot on your skin, or any new symptom of skin cancer or melanoma, should alert you to contact your healthcare provider.

Be on the lookout for irregular-looking spots on your skin, new spots or ones that change size, shape or color.

Are There Other Signs of Melanoma?

Besides doing the ABCDE skin assessment, look for other melanoma symptoms including:

• Fluid (like blood or puss) on a spot’s surface
• Itching, redness or pain
• New inflammation outside the spot’s original borders
• Color (pigmentation) that spreads to surrounding areas
• A spot that won’t heal

What Are Signs Of Other Types of Skin Cancers?

It’s also important to check for other types of skin cancer: basal cell carcinoma, which is the most common; and squamous cell carcinoma, a type that grows slowly and deeply.

Basal cell carcinoma can be a dome-shaped growth; a shiny, pinkish area; a black or brown growth; a white or yellow waxy growth; or a sore that heals then returns.

Squamous cell carcinoma can be a crusted or rough bump; a red, rough flat area; a dome-shaped bump that grows and bleeds; or a sore that either does not heal or heals and returns.

Listen Now: Skin Cancer Screening, Self-Detection, and Sunscreen Tips

With skin cancer being the most common cancer in the United States and worldwide, it is imperative people do everything they can to protect themselves from the sun’s rays—starting from a very young age. Dr. Juliana Meyer, melanoma surgeon with Franciscan Health, discusses skin cancer prevention and detection in the Franciscan DocPod Podcast.

What Should I Do If I See Changes In My Skin?

"The next step up from self-detection is to talk to your primary care doctor or your dermatologist," Dr. Meyer said. "If for some reason you don't have a primary care doc who's comfortable with skin checks, I always recommend a dermatologist once a year just to take a look from head to toe and make sure that those moles, those lesions all look the same."