Dark side of the sun: What you need to know about sun exposure

December 01, 2012
Dark side of the sun

As a specialist in skin disorders and cancers, UC Irvine dermatologist Dr. Janellen Smith sees firsthand what too much sun can do. Sun exposure is the No. 1 cause of premature aging; it can also be deadly.

Each year, more than one million Americans are diagnosed with skin cancer, the most common of all cancers. About 50,000 of these cases involve melanoma, which is the most serious form of skin cancer. If not treated promptly, melanoma cells can spread to other parts of the body and prove fatal.

Overexposure to sunlight can exacerbate wrinkles, age spots and dilated blood vessels. It also can alter the skin’s texture to look older. It can damage the eyes. Skin conditions such as lupus can worsen with prolonged sun exposure. People who take certain medications, such as antibiotics, high blood pressure medicines or retinoids are more sensitive to the suns rays.

Smith, a UC Irvine dermatology professor affiliated with UC Irvine’s Chao Family Comprehensive Cancer Center and the Melanoma Center, stresses that people—especially those in sun-worshipping Southern California—should be aware of the health risks associated with prolonged sun exposure and take proper precautions.

Smith, who also sees patients at UC Irvine’s Dermatology Center in Irvine, answers the following questions about sun exposure and how to protect the skin:

Q: Who should be most concerned about excessive sun exposure?

A: The sun is harmful to all skin types, but people with lighter skin that freckles easily are the most at risk. Another big risk factor is a family history of skin cancer.

Although skin cancer is less prevalent among people with darker skin, some, especially Latinos, are developing skin cancers at an increased rate. Asians and African Americans are not immune to melanoma either. When it does appear, it's often on the palms, on the soles of the feet or under the fingernails.

Q: Why should people be concerned about getting too much sun?

A: The three most important reasons are the risk of developing skin cancer, faster aging and interactions the sun can have with certain medications. When I talk to patients, I often emphasize the ravages of aging, because they never think they'll get cancer.

Q: What types of cancer can people get from sun exposure?

A: There are three main types of skin cancer: basal cell carcinoma, squamous cell carcinoma and melanoma. Basal cells are the most common, but melanomas are the most deadly.

Q: How does excess sun lead to melanoma?

A: Chronic exposure to the sun’s ultraviolet rays leads to the development of nonmelanoma skin cancers. Sporadic, high-intensity sun exposure leads to the development of melanomas. There is some crossover, but this is often the case. Essentially, ultraviolet rays damage the skin and overwhelm the body's repair mechanisms.

Q: What can be done for sun-damaged skin?

A: The sooner you get out of the habit of excess sun exposure the better. It may sometimes seem as though this does no good because some of the damage previously incurred is still developing. Eventually you will reap the benefits. UC Irvine Medical Center dermatologists have many methods to help you. There are creams, laser treatments and fillers that can go a long way toward returning your skin to peak condition.

Q: What products help protect the skin?

A: The key is to use “broad spectrum” sun protection products that protect the skin from both ultraviolet A and B rays.

Look for a sunscreen with a minimum sun protection factor (SPF) of 30 to protect against ultraviolet B (UVB) rays. Look also look for sunscreens containing zinc oxide, titanium dioxide, avobenzone, mexoryl or Helioplex® to protect against ultraviolet A (UVA) rays, which penetrate the skin more deeply, are responsible for premature aging and contribute to the development of skin cancer.

Q. Which ones should be avoided?

A: Do not use baby oil, cocoa butter or similar products. They do not protect the skin from ultraviolet rays.

Q. What is best way to use sunscreens?

A. Apply generously. It takes about one ounce (two tablespoons) of sunscreen to cover the entire body. As a rule of thumb, a pea size amount should cover an area about the size of your palm. At least 80 percent of skin cancers occur on the head and neck, mostly due to day-to-day exposure to the sun. Get in the habit of putting sunscreen on in the morning after you brush your teeth.

For best results, apply at least 30 minutes before significant sun exposure. Reapply sunscreen every 2 hours and more often if you are swimming, exercising, or sweating.

Q. What other products protect the skin from sun exposure?

A. Hats and tightly woven clothing also are protective, and some companies make clothing with sun protection factor (SPF) ratings. As a rule, light-colored, lightweight and loosely-woven fabrics offer minimal protection from the sun. For example, white cotton T-shirts provides an average ultraviolet protection factor (UPF) of 7. A green cotton T-shirt offers an UPF of 10. On the other hand, thicker fabrics such as velvet may provide a UPF of 50.

Specially treated fabrics are now used in some light-weight clothing that offers protection from UVA and UVB. These clothes have been specially treated with UV absorbing dyes that provide UPF of 50 or more. There are also laundry additives containing a sunscreen that can last through numerous washings.

Q: What can people do to maximize good skin health?

A: Avoid the sun during the peak hours of 10 a.m. to 4 p.m., and use sunscreen and sun-protective clothing. Sometimes it's best to think of your day upside down: If you normally go to the beach in the afternoon and the movies at night, think about making a switch. There is nothing quite as fine as walking along the beach as the sun goes down, and movie theaters are much less crowded in the afternoon.

Learn more about Dr. Smith »

For more information or schedule an appointment, call 949-824-0606.

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