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What’s that spot? When to see a doctor about something suspicious on your skin

Doctor examining a spot on patients skin

Skin cancer is the most common type of cancer in the United States. It’s also very treatable. Here’s what you need to know.

You were looking in the mirror and saw a strange spot on your back. And it got you thinking: Is this something I need to be worried about?

Many spots on your skin are harmless. But there are times when it’s a good idea to get your skin checked by a doctor.

The reason? Skin cancer is the most common type of cancer in the United States. Every day, about 9,500 people find out they have skin cancer.1 And it can be dangerous if it’s not treated.

But here’s the good news: When caught early, most skin cancers are treatable.1 Plus, there’s a lot you can do to protect your skin. Here’s what you need to know.

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What is skin cancer, and how can it affect you?

Skin cancer happens when your skin cells grow abnormally.2 Here are some reasons why that might happen:1

  • You spend a lot of time in the sun.
  • You spend a lot of time doing indoor tanning.
  • You have a family history of skin cancer.
  • You have skin that freckles or burns easily

The top layer of your skin (epidermis) is where most skin cancers start. And there are several types:2

Basal cell and squamous cell cancers

These skin cancers are the most common category of skin cancer. They’re also the most treatable. About 3 million Americans are affected by them every year.1 They’re usually found on sun-exposed areas of the body. Those can include the face, arms and neck.

Basal cell cancer. This is the most common type of cancer. About 8 in 10 skin cancers are basal cell cancers. Basal cell cancer starts in the lower part of the top layer of your skin (basal cell layer).2

This type of cancer can be sneaky. People often think they just have a pimple or bug bite, says Howard Horlick, MD. He’s an Optum dermatologist in Port Jefferson Station and Syosset, New York. The spots are also normally the color of your skin. On lighter skin, they can also look pink, and on darker skin, they can also look black.

“Typically, they have a shiny surface,” says Dr. Horlick. “But they’re slow growing.”

So, how you can you tell if the spot might be cancer? Dr. Horlick lists some of the key warning signs:3

  • It’s getting bigger.
  • It isn’t healing.
  • It may bleed, even when touched lightly.

Squamous cell cancer. This type of cancer starts on the outer part of the top layer of your skin. About 2 in 10 skin cancers are squamous cell cancers.2 These can appear in many forms. They can be scaly reddish patches, open sores or wart-like growths. They can also develop in an old scar. Sometimes they look like a small horn growing from the skin.4

These cancers often appear on sun-exposed parts of the body. These include:2

  • Backs of hands
  • Ears
  • Face
  • Lips
  • Neck

In people with darker skin tones, squamous cell cancers can develop in areas that aren’t exposed to the sun.

Remember: These types of cancer are highly treatable if caught early. Common ways of treating these skin cancers include:5

  • Surgery. A doctor removes the cancer cells from the body. They might be frozen and killed, shaved off or cut off.5,6
  • Chemical peel. This is when a doctor applies a chemical to the skin and the top layer comes off.5
  • Immunotherapy. A treatment that helps your immune system find and fight cancer.6
  • Photodynamic therapy. When a doctor uses a mix of medications and a special light to kill cancer cells.5,6
  • Radiation therapy. A specialist uses high-energy X-rays and other radiation to kill cancer cells.5,6
  • Chemotherapy. These are drugs that kill cancer cells. Typically, these types of cancer are treated with chemotherapy creams that are applied to the skin.6

Looking for a doctor who gets you? We have more than 60,000 doctors at more than 2,000 locations. Our team will help you get the care you need, when and where you need it. Find care near you.


Melanoma is a much less common form of skin cancer. Only about 1 out of 100 skin cancers are melanoma, according to the American Cancer Society.7 But it can be a lot more dangerous. And if it’s not caught early enough, it can be more difficult for doctors to treat.8

Melanoma can look like a mole on your skin. Sometimes it can grow from an existing mole. Or it can appear on the skin out of nowhere.

Warning signs of melanoma. Many skin doctors follow the “ABCDEs of melanoma.”9 Here’s what each letter stands for:

  • A is for asymmetry. If the sides of a spot don’t look the same (i.e., “asymmetry”), that can be a cause for concern, says Dr. Horlick.
  • B is for border. The spot has an irregular or poorly defined border. You want to see sharp borders, and should be able to see where the spot starts and ends. If it looks like a smudge, that could be a warning sign, too, says Dr. Horlick.
  • C is for color. Does the spot have a certain color? If the spot is one or two colors, that’s usually OK, says Dr. Horlick. But if it’s more than two colors and not brown or black, it could be a problem. For example, if the spot is purple or white, that can be a warning sign.
  • D is for diameter. “If the diameter is wider than the end of an eraser on a pencil, that might be concerning,” says Dr. Horlick. But that’s not an exact measurement, he says. And a smaller spot can also be a problem.
  • E is for evolving. Any spot or mole that changes shape over time can be a warning sign of melanoma.9

Worried about a spot? The best thing you can do is schedule an appointment with a dermatologist. They can help you figure out if the spot needs more attention.

Skin-protection tips

The best way to avoid skin cancer: Protect your skin from damaging UV rays. Keep these skin-safety tips in mind:

1. Wear sunscreen that’s at least SPF 30. Make sure it says “broad spectrum” on the label.10 That means it protects against UVA and UVB rays. Put it on your face, neck, hands and any other exposed skin every day. And put it on at least 15 minutes before you go outside. Reapply every 2 hours, or sooner if you’re swimming or sweating a lot.10

2. Don’t forget a hat and sunglasses. A hat with a wide brim will help protect your face and neck.11 And sunglasses that offer UV protection can help in two ways. They lower your chance of developing cataracts, and they lower your chance of developing skin cancer around your eyes.12 Even with these items, it’s best to head for the shade between 10 a.m. and 2 p.m. That’s when the sun’s rays are strongest.11

3. Wear sun-protective clothing. Long-sleeved shirts and coverups made from special SPF fabric are another good way to shield your skin. They keep the sun’s damaging UV rays from reaching your skin. Of course, you still want to put sunscreen on any skin that is not covered.

4. Check your skin often. Dr. Horlick advises checking your skin from head to toe once a month. And be aware that a spot could appear on your back, and you may never know it’s there. So have someone you trust, such as your spouse or a family member, check your back for you. “If they see something different, that’s when you should go to a dermatologist,” he says.

5. Just say no to indoor tanning. There is no such thing as a safe tan. UV light from tanning beds is similar to that of the sun and can increase your risk of skin cancer.13

You can buy sunscreen and other sun-protection products at the Optum Store — all from the comfort of home. Start exploring.


  1. American Academy of Dermatology. Skin cancer incidence rates. Last updated April 22, 2022. Accessed March 28, 2023.
  2. American Cancer Society. What are basal and squamous cell skin cancers? Last revised July 26, 2019. Accessed March 28, 2023.
  3. American Academy of Dermatology. How can I tell if I have skin cancer? Accessed March 30, 2023.
  4. American Academy of Dermatology. What are the signs and symptoms of squamous cell carcinoma? Accessed March 30, 2023.
  5. National Cancer Institute. Skin cancer treatment (PDQ) — patient version. Article updated August 27, 2021. Accessed March 30, 2023.
  6. American Cancer Society. Skin Cancer Treatments. Last updated 2021. Article accessed April 20, 2023.
  7. American Cancer Society. Key statistics for melanoma skin cancer. Last revised January 12, 2023. Accessed March 27, 2023.
  8. American Cancer Society. Treatment of melanoma skin cancer, by stage. Last revised March 22, 2022. Accessed March 30, 2023.
  9. American Academy of Dermatology. What to look for: ABCDEs of melanoma. Accessed March 27, 2023.
  10. American Academy of Dermatology. How to apply sunscreen. Accessed March 30, 2023.
  11. American Academy of Dermatology. Practice Safe Sun. Last updated April 18, 2022. Article accessed April 20, 2023.
  12. Centers for Disease Control and Prevention. Sun Safety. Last reviewed April 18, 2023. Article accessed April 20, 2023.
  13. American Academy of Dermatology. Indoor tanning. Accessed April 28, 2023.

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