Hope & Healing: The UF Health Blog

Be Safe in the Sun: How to Protect Yourself From Skin Cancer and Other Solar-Related Conditions

The school year has begun, which in many parts of the country signals that fall and cooler temperatures are right around the corner. However, in Florida, the sun’s rays remain intense well after the first school bells ring. That means two things: Business as usual for outdoor activities and that we need to remain vigilant in protecting ourselves from ultraviolet rays and their damaging effects. In the spirit of the American Cancer Society’s Summer Sun Safety Month, we met with Michael Lavery, MD, a clinical assistant professor in the University of Florida Department of Dermatology, to discuss the effects of too much sun exposure and tips for being cautious outdoors.

Q: What causes skin cancer?

ML: Skin cancer is caused when mutations occur in the DNA of skin cells, leading to the development of abnormal cells. These cells rapidly divide, forming cancerous cells. While certain genetic disorders increase the risk of developing skin cancer, excess exposure to ultraviolet rays is the leading cause of skin cancer in America. The most common ultraviolet, or UV, rays are UVA and UVB. UVA rays account for 95% of the UV radiation that makes it to Earth. These rays can penetrate through glass windows, clouds and water and into the skin’s inner layers. UVA rays are primarily responsible for accelerated skin aging, including wrinkles, sun spots and skin darkening. UVB rays do not penetrate as deeply into the skin as UVA rays but are responsible for sunburns and skin cell damage, which can lead to DNA mutations and increased skin cancer risk. UVB exposure can also lead to cataracts.

A child on their parent's shoulders

Q: What are the best ways to prevent skin cancer?

ML: The best way to protect your skin is to be vigilant when outdoors. Apply and regularly reapply plenty of sunscreen, wear UV-protective clothing and limit the amount of time outdoors during peak UV times between 10 a.m. to 2 p.m. A helpful tip is if your shadow is shorter than you, then you should seek shade.

Q: Can someone be at risk for skin cancer even though their normal routine does not include a lot of time outdoors?

ML: UVA rays can penetrate through window glass, including in cars and public transport. Applying a UV protective film can help reduce this exposure. UV rays can also reflect off surfaces, including tarmac, buildings, water, sand and snow. Spending even a small amount of time outdoors can lead to exposure to harmful UV rays.

Q: How important is sunscreen or lotion with SPF in preventing skin cancer? How should an individual select which sunscreen and SPF is best for them?

ML: It is important to apply sunscreen that has both UVA and UVB coverage on a daily basis. UVB coverage is denoted by the sun protector factor, or SPF. SPF is a measure of the amount of UV radiation required to cause a sunburn with sunscreen application, as compared with the amount of UV radiation required to cause a sunburn with no sunscreen application. The higher the SPF, the more sun protection that is provided. For example, SPF 15 filters out about 93% of UVB rays, compared to SPF 30, which filters out 96.7%. The term ‘broad spectrum’ on sunscreens denotes UVA protection. It is important to apply a sunscreen of SPF 30 or higher, with broad spectrum, to ensure protection against UVA and UVB. Applying sunscreen that is ‘water resistant’ can be useful, but people should still reapply every two hours, or after water activities, to maintain optimal protection. Sunscreen is available in many forms. In general, lotions are the easiest to apply, and sprays are useful for the scalp. Creams and ointments are available but are less common since they are thick and greasy compared with lotions.

Q: How often should individuals reapply sunscreen? And what are the most common sunscreen mistakes?

ML: Sunscreen should be applied 20-30 minutes before going outside. Sunscreen should also be reapplied every two hours, or after swimming, water sports or exercise. Most individuals do not apply enough sunscreen. In general, an adult should apply one teaspoon of sunscreen to each arm and leg, and to the face, neck, and front and back of body. This equates to around 7 teaspoons of sunscreen for a whole-body application. It is also important to apply sunscreen to the ears, neck, scalp and feet. A lip balm with SPF 30 or higher can be applied to the lips. All infants should be kept out of direct sunlight and wear protective clothing. In general, sunscreen application is safe for those older than 6 months of age. The myth that sunscreen application prevents the absorption of vitamin D is unfounded and has not been proven in clinical studies.

Q: In addition to sunscreen, how else can individuals keep safe in the sun?

ML: Avoiding direct sun exposure during peak UV rays and, ideally, spending time in the shade between 10 a.m. to 4 p.m. are the best ways to keep safe in the sun. UV protective clothing offers further protection. There are a multitude of companies providing these, both online and in-store, in a variety of different colors and styles. These can include UV swimwear, shirts and pants for outdoor activities, neck gaiters, hats, arm sleeves and gloves. These can be especially useful with long commutes to work or for leisure. Wearing a wide-brimmed UV hat that also covers the ears and neck along with UV protection sunglasses is also important. Lastly, tanning beds, tanning lamps and UV lamps should be avoided. Multiple states have banned the use of indoor tanning beds for minors.

Q: In addition to skin cancer, what other skin conditions can be caused by exposure to the sun?

ML: Several skin conditions can be aggravated or induced by UV exposure, including solar urticaria (hives), lupus and certain blistering disorders. Some medications can make individuals more prone to sunburn or rashes. These include antibiotics (tetracyclines), nonsteroidal anti-inflammatory drugs (ibuprofen, naproxen), acne medications (isotretinoin) and anti-hypertensives. UV rays can also cause premature aging, wrinkles, freckles, irregular skin pigmentation, rough skin and cataracts.

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