Sun Exposure & Skin Cancer

Overview

What changes in the skin occur due to exposure to the sun?

Exposure to sun causes most of the wrinkles and age spots on our faces. People think a glowing complexion means good health, but skin color obtained from being in the sun can actually speed up the effects of aging and increase the risk of developing skin cancer.

Sun exposure causes most of the skin changes that we think of as a normal part of aging. Over time, the sun's ultraviolet (UV) light damages the fibers in the skin called elastin. When these fibers break down, the skin begins to sag, stretch, and lose its ability to go back into place after stretching. The skin also bruises and tears more easily in addition to taking longer to heal. So while sun damage to the skin may not be apparent when you're young, it will definitely show later in life. The sun can also cause issues for your eyes, eyelids, and the skin around the eyes.

Changes in the skin related to sun exposure:

  • Precancerous (actinic keratosis) and cancerous (basal cell carcinoma, squamous cell carcinoma, and melanoma) skin lesions caused by loss of the skin's immune function.
  • Benign tumors.
  • Fine and coarse wrinkles.
  • Freckles; discolored areas of the skin, called mottled pigmentation; and sallowness, yellow discoloration of the skin.
  • Telangiectasias, the dilation of small blood vessels under the skin.
  • Elastosis, the destruction of the elastic tissue causing lines and wrinkles.

What is skin cancer?

Skin cancer is the most common form of cancer in the US, and the number of cases continues to rise. It is the uncontrolled growth of abnormal skin cells. While healthy cells grow and divide in an orderly way, cancer cells grow and divide in a rapid, haphazard manner. This rapid growth results in tumors that are either benign (noncancerous) or malignant (cancerous).

There are three main types of skin cancer:

Basal cell and squamous cell cancers are less serious types and make up 95% of all skin cancers. Also referred to as non-melanoma skin cancers, they are highly curable when treated early.

Melanoma, made up of abnormal skin pigment cells called melanocytes, is the most serious form of skin cancer and causes 75% of all skin cancer deaths. Left untreated, it can spread to other organs and is difficult to control.

Symptoms and Causes

What causes skin cancer?

Ultraviolet (UV) radiation from the sun is the number one cause of skin cancer, but UV light from tanning beds is just as harmful. Exposure to sunlight during the winter months puts you at the same risk as exposure during the summertime.

Cumulative sun exposure causes mainly basal cell and squamous cell skin cancer, while episodes of severe blistering sunburns, usually before age 18, can cause melanoma later in life. Other less common causes are repeated X-ray exposure, scars from burns or disease, and occupational exposure to certain chemicals.

Ultraviolet A (UVA) and Ultraviolet B (UVB) rays also affect the eyes and the skin around the eyes. Sun exposure may lead to cataracts, cancer of the eyelids, and possibly macular degeneration.

Who is at risk for skin cancer?

Although anyone can get skin cancer, the risk is greatest in people who have fair or freckled skin that burns easily, light eyes and blond or red hair. Darker-skinned individuals are also susceptible to all types of skin cancer, although their risk is lower.

In addition to complexion, other risk factors include having a family history or personal history of skin cancer, having an outdoor job, and living in a sunny climate. A history of severe sunburns and an abundance of large and irregularly shaped moles are risk factors unique to melanoma.

What are the signs and symptoms of skin cancer?

The most common warning sign of skin cancer is a change on the skin, typically a new mole, a new skin lesion or a change in an existing mole.

  • Basal cell carcinoma may appear as a small, smooth, pearly, or waxy bump on the face, or neck, or as a flat, pink/red- or brown-colored lesion on the trunk, arms or legs.
  • Squamous cell carcinoma can appear as a firm, red nodule, or as a rough, scaly, flat lesion that may itch, bleed and become crusty. Both basal cell and squamous cell cancers mainly occur on areas of the skin frequently exposed to the sun, but can occur anywhere.
  • Melanoma usually appears as a pigmented patch or bump. It may resemble a normal mole, but usually has a more irregular appearance.

When looking for melanoma, think of the ABCDE rule that tells you the signs to watch for:

  • Asymmetry: The shape of one half doesn't match the other.
  • Border: Edges are ragged or blurred.
  • Color: Uneven shades of brown, black, tan, red, white or blue.
  • Diameter: A significant change in size (greater than 6 mm).
  • Evolution: Changes in the way a mole or lesion looks or feels (itchy, bleeding, etc).

Diagnosis and Tests

How is skin cancer diagnosed?

Skin cancer is suspected by its appearance on the skin. The diagnosis must be confirmed with a biopsy. This involves taking a sample of the tissue, which is then placed under a microscope and examined by a dermatopathologist, a doctor who specializes in examining skin cells. Sometimes a biopsy can remove all of the cancer tissue and no further treatment is needed.

Management and Treatment

How is skin cancer treated?

Treatment of skin cancer depends on the type and extent of the disease. Treatment is individualized and is determined by the type of skin cancer, its size and location, and the patient's preference.

Standard treatments for non-melanoma skin cancer (basal cell or squamous cell carcinomas) include:

  • Mohs surgery (for high-risk non-melanoma skin cancers): Skin-sparing excision of cancer with complete peripheral and deep margin assessment.
  • Excision.
  • Electrodesiccation and curettage: Scraping away the skin cancer cells followed by electrosurgery.
  • Cryosurgery.
  • Radiation treatment.
  • Drugs (chemotherapy, biological response modifiers to destroy cancer cells).

Standard treatments for melanoma include:

  • Wide surgical excision.
  • Sentinel lymph node mapping (for deeper lesions): to determine if the melanoma has spread to local lymph nodes.
  • Drugs (chemotherapy, biological response modifiers).
  • Radiation therapy.
  • New methods in clinical trials are sometimes used to treat skin cancer.

Prevention

How can I help prevent sun damage and ultimately, skin cancer?

Nothing can completely undo sun damage, although the skin can sometimes repair itself. So, it's never too late to begin protecting yourself from the sun. Your skin does change with age; for example, you sweat less and your skin can take longer to heal, but you can delay these changes by limiting sun exposure.

Maintaining healthy skin

  • Stop smoking: People who smoke tend to have more wrinkles than nonsmokers of the same age, complexion, and history of sun exposure. The reason for this difference is unclear. It may be because smoking interferes with normal blood flow in the skin.
  • Apply sunscreen with a sun protection factor (SPF) of 30 or greater 30 minutes before sun exposure and then every 2 to 3 hours thereafter. Reapply sooner if you get wet or perspire significantly.
  • Select cosmetic products and contact lenses that offer UV protection.
  • Wear sunglasses with total UV protection.
  • Avoid direct sun exposure as much as possible during peak UV radiation hours between 10 am and 4 pm.
  • Perform skin self-exams regularly to become familiar with existing growths and to notice any changes or new growths.
  • Relieve dry skin using a humidifier at home, bathing with soap less often (instead, use a moisturizing body wash), and using a moisturizing lotion.
  • Become a good role model and foster skin cancer prevention habits in your child. Eighty percent of a person's lifetime sun exposure is acquired before age 18.

Understanding UV index

You might see ratings from the UV index on weather reports. The numbers represent the risk of unprotected sun exposure to the average person. You may think that the lower index numbers mean you do not have to take action, but the risk of sun exposure to unprotected skin always exists. You might also think that cloudy days mean you can spend unlimited time in the sun, but this is not true.

0-2: Low

At the low stage, experts advise you to wear sunglasses if the sun is bright. Use sunscreen and protective clothing if you burn easily.

3-5: Moderate

At the moderate stage, you should cover up and use sunscreen. Avoid direct sunlight at midday, when the sun is most powerful. Stay in the shade.

6-7: High

At the high stage, you should use all protections against sun damage (protective clothing, wearing a hat and sunglasses, using sunscreen). Limit time in the the sun from 10 am to 4 pm.

8-10: Very high

At the very high stage, you should be extra careful, using clothing, hats, sunscreen and sunglasses. Avoid the sun between 10 am and 4 pm. Your skin can burn quickly at this stage and will be injured.

11 or higher (11+): Extreme

At the extreme stage, you should use all methods of prevention. It will only take minutes of exposure to result in a burn. Do not go out in the sun from 10 am to 4 pm. Wear protective clothing, a hat, sunglasses and sunscreen. At this stage and all others, remember that snow, sand, and water all increase UV exposure by reflecting the sun’s rays.

When should I call a doctor about sun damage?

If you notice any changes in your skin that worry you, contact your doctor at once. It is important to perform regular skin checks to notice any new spots or changes in existing lesions. It is also important to get regular eye exams. Contact your doctor if you have changes in vision.

Last reviewed by a Cleveland Clinic medical professional on 10/10/2019.

References

  • Tung R, Vidimos A. Melanoma. In: Carey WD, ed. Cleveland Clinic: Current Clinical Medicine 2010. 2nd ed. Philadelphia, Pa: Saunders Elsevier; 2010:section 3.
  • Tung R, Vidimos A. Nonmelanoma skin cancer. In: Carey WD, ed. Cleveland Clinic: Current Clinical Medicine 2010. 2nd ed. Philadelphia, Pa: Saunders Elsevier; 2010:section 3.
  • Environmental Protection Agency. The UV Index Scale. Accessed 12/4/2019.
  • Skin Cancer Foundation. Sun Protection. Accessed 12/4/2019.

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy