Skin cancer is the most common form of cancer in the United States. The two most common types of skin cancer—basal cell and squamous cell carcinomas—are highly curable, but can be disfiguring and costly. Melanoma, the third most common skin cancer, is more dangerous and causes the most deaths. The majority of these three types of skin cancer are caused by exposure to ultraviolet (UV) light.

Ultraviolet (UV) Light
Ultraviolet (UV) rays are an invisible kind of radiation that comes from the sun, tanning beds, and sunlamps. UV rays can penetrate and change skin cells.

The three types of UV rays are ultraviolet A (UVA), ultraviolet B (UVB), and ultraviolet C (UVC)—

  • UVA is the most common kind of sunlight at the earth’s surface, and reaches beyond the top layer of human skin. Scientists believe that UVA rays can damage connective tissue and increase a person’s risk of skin cancer.
  • Most UVB rays are absorbed by the ozone layer, so they are less common at the earth’s surface than UVA rays. UVB rays, which help produce vitamin D in the skin, don’t reach as far into the skin as UVA rays, but they still can be damaging.
  • UVC rays are very dangerous, but they are absorbed by the ozone layer and do not reach the ground.

In addition to sunburn, too much exposure to UV rays can change skin texture, cause the skin to age prematurely, and can lead to skin cancer. UV rays also have been linked to eye conditions such as cataracts.

The National Weather Service and the Environmental Protection Agency developed the UV Index to forecast the risk of overexposure to UV rays. It lets you know how much caution you should take when working, playing, or exercising outdoors.

The UV Index predicts exposure levels on a 1 to 15 scale; higher levels indicate a higher risk of overexposure. Calculated on a next-day basis for dozens of cities across the United States, the UV Index takes into account clouds and other local conditions that affect the amount of UV rays reaching the ground.

What Are the Risk Factors for Skin Cancer?
People with certain risk factors are more likely than others to develop skin cancer. Risk factors vary for different types of skin cancer, but some general risk factors are having—

  • A lighter natural skin color.
  • Family history of skin cancer.
  • A personal history of skin cancer.
  • Exposure to the sun through work and play.
  • A history of sunburns, especially early in life.
  • A history of indoor tanning.
  • Skin that burns, freckles, reddens easily, or becomes painful in the sun.
  • Blue or green eyes.
  • Blond or red hair.
  • Certain types and a large number of moles.

Tanning and Burning
Ultraviolet (UV) rays come from the sun or from indoor tanning (using a tanning bed, booth, or sunlamp to get tan). When UV rays reach the skin’s inner layer, the skin makes more melanin. Melanin is the pigment that colors the skin. It moves toward the outer layers of the skin and becomes visible as a tan.

A tan does not indicate good health. A tan is a response to injury, because skin cells signal that they have been hurt by UV rays by producing more pigment.

People burn or tan depending on their skin type, the time of year, and how long they are exposed to UV rays. The six types of skin, based on how likely it is to tan or burn, are—

  1. Always burns, never tans, sensitive to UV exposure.
  2. Burns easily, tans minimally.
  3. Burns moderately, tans gradually to light brown.
  4. Burns minimally, always tans well to moderately brown.
  5. Rarely burns, tans profusely to dark.
  6. Never burns, deeply pigmented, least sensitive.

Although everyone’s skin can be damaged by UV exposure, people with skin types I and II are at the highest risk.

What Are the Symptoms of Skin Cancer?
A change in your skin is the most common sign of skin cancer. This could be a new growth, a sore that doesn’t heal, or a change in a mole. Not all skin cancers look the same.

A simple way to remember the signs of melanoma is to remember the A-B-C-D-Es of melanoma

  • “A” stands for asymmetrical. Does the mole or spot have an irregular shape with two parts that look very different?
  • “B” stands for border. Is the border irregular or jagged?
  • “C” is for color. Is the color uneven?
  • “D” is for diameter. Is the mole or spot larger than the size of a pea?
  • “E” is for evolving. Has the mole or spot changed during the past few weeks or months?

Talk to your doctor if you notice changes in your skin such as a new growth, a sore that doesn’t heal, a change in an old growth, or any of the A-B-C-D-Es of melanoma.

What Can I Do to Reduce My Risk of Skin Cancer?
Protection from ultraviolet (UV) radiation is important all year round, not just during the summer or at the beach. UV rays from the sun can reach you on cloudy and hazy days, as well as bright and sunny days. UV rays also reflect off of surfaces like water, cement, sand, and snow. Indoor tanning (using a tanning bed, booth, or sunlamp to get tan) exposes users to UV radiation.

The hours between 10 a.m. and 4 p.m. Daylight Saving Time (9 a.m. to 3 p.m. standard time) are the most hazardous for UV exposure outdoors in the continental United States. UV rays from sunlight are the greatest during the late spring and early summer in North America.

CDC recommends easy options for protection from UV radiation—

  • Stay in the shade, especially during midday hours.
  • Wear clothing that covers your arms and legs.
  • Wear a hat with a wide brim to shade your face, head, ears, and neck.
  • Wear sunglasses that wrap around and block both UVA and UVB rays.
  • Use sunscreen with sun protection factor (SPF) 15 or higher, and both UVA and UVB protection.
  • Avoid indoor tanning.

What Screening Tests Are There?
The U.S. Preventive Services Task Force (USPSTF) has concluded there is not enough evidence to recommend for or against routine screening (total body examination by a doctor) to find skin cancers early. This recommendation is for people who do not have a history of skin cancer and who do not have any suspicious moles or other spots. Report any unusual moles or changes in your skin to your doctor. Also talk to your doctor if you are at increased risk of skin cancer.

How Can I Protect My Children from the Sun?
Just a few serious sunburns can increase your child’s risk of skin cancer later in life. Kids don’t have to be at the pool, beach, or on vacation to get too much sun. Their skin needs protection from the sun’s harmful ultraviolet (UV) rays whenever they’re outdoors.

  • Seek shade. UV rays are strongest and most harmful during midday, so it’s best to plan indoor activities then. If this is not possible, seek shade under a tree, an umbrella, or a pop-up tent. Use these options to prevent sunburn, not to seek relief after it’s happened.
  • Cover up. When possible, long-sleeved shirts and long pants and skirts can provide protection from UV rays. Clothes made from tightly woven fabric offer the best protection. A wet T-shirt offers much less UV protection than a dry one, and darker colors may offer more protection than lighter colors. Some clothing certified under international standards comes with information on its ultraviolet protection factor.
  • Get a hat. Hats that shade the face, scalp, ears, and neck are easy to use and give great protection. Baseball caps are popular among kids, but they don’t protect their ears and neck. If your child chooses a cap, be sure to protect exposed areas with sunscreen.
  • Wear sunglasses. They protect your child’s eyes from UV rays, which can lead to cataracts later in life. Look for sunglasses that wrap around and block as close to 100% of both UVA and UVB rays as possible.
  • Apply sunscreen. Use sunscreen with at least SPF 15 and UVA and UVB protection every time your child goes outside. For the best protection, apply sunscreen generously 30 minutes before going outdoors. Don’t forget to protect ears, noses, lips, and the tops of feet.

Take sunscreen with you to reapply during the day, especially after your child swims or exercises. This applies to waterproof and water-resistant products as well.

Follow the directions on the package for using a sunscreen product on babies less than 6 months old. All products do not have the same ingredients; if your or your child’s skin reacts badly to one product, try another one or call a doctor. Your baby’s best defense against sunburn is avoiding the sun or staying in the shade.

Keep in mind, sunscreen is not meant to allow kids to spend more time in the sun than they would otherwise. Try combining sunscreen with other options to prevent UV damage.

Too Much Sun Hurts
Turning pink? Unprotected skin can be damaged by the sun’s UV rays in as little as 15 minutes. Yet it can take up to 12 hours for skin to show the full effect of sun exposure. So, if your child’s skin looks “a little pink” today, it may be burned tomorrow morning. To prevent further burning, get your child out of the sun.

Tan? There’s no other way to say it—tanned skin is damaged skin. Any change in the color of your child’s skin after time outside—whether sunburn or suntan—indicates damage from UV rays.

Cool and cloudy? Children still need protection. UV rays, not the temperature, do the damage. Clouds do not block UV rays, they filter them—and sometimes only slightly.

Oops! Kids often get sunburned when they are outdoors unprotected for longer than expected. Remember to plan ahead, and keep sun protection handy—in your car, bag, or child’s backpack.

Are There Benefits to Spending Time Outdoors?
Spending time outdoors can improve overall health and wellness. The outdoors offers many opportunities to be physically active. Time outdoors may also promote mental health and stress reduction. While enjoying the benefits of being outdoors, people can decrease skin cancer risk from too much UV exposure by using sun protection. Protect yourself by staying in the shade, wearing protective clothing, and applying and re-applying a broad spectrum sunscreen with a sun protection factor (SPF) of 15 or higher.

Ultraviolet (UV) rays from the sun can stimulate production of vitamin D in the skin. Having little or no sun exposure may put a person at risk for low levels of vitamin D, but too much UV exposure from the sun or artificial sources can increase risk of skin cancers and eye disease. CDC data[PDF-316KB] show that most people in the United States are getting enough vitamin D. The amount of vitamin D a person’s skin makes when they are in the sun depends on many factors, including skin tone, geographic location, weather conditions, time of year, and time of day.

The skin can produce only a limited amount of vitamin D at one time. Once the body has reached this limit, spending more time in the sun will not continue to increase vitamin D levels. However, continued time in the sun will increase your skin cancer risk. There is no known level of UV exposure that would increase vitamin D levels without also increasing skin cancer risk. Vitamin D can be obtained safely through food and dietary supplements without the risks associated with overexposure to UV.
The skin can produce only a limited amount of vitamin D at one time. Once the body has reached this limit, spending more time in the sun will not continue to increase vitamin D levels. However, continued time in the sun will increase your skin cancer risk. There is no known level of UV exposure that would increase vitamin D levels without also increasing skin cancer risk. Vitamin D can be obtained safely through food and dietary supplements without the risks associated with overexposure to UV.