How does the sun damage skin?
Sunlight contains ultraviolet (UV) rays that can pass through the outer layers of the skin and cause damage. Two types of UV rays affect skin health: UVA and UVB. Of the two, UVA is the more dangerous one.
UV light is not all bad. The body uses it to make vitamin D to help build strong bones and fight off infections. But just a few minutes of sun exposure is enough to supply all the vitamin D most people need. After that, sun exposure does more harm than good.
“UV damage can cause a spectrum of changes to the skin,” says Meredith McKean, MD, MPH, director of Melanoma and Skin Cancer Research at Sarah Cannon Research Institute. “Most concerns would be skin cancers, such as squamous cell carcinoma, basal cell carcinoma, melanoma and Merkel cell carcinoma.”
What skin conditions are caused by sun damage?
Skin conditions caused by sun damage range from wrinkles to skin cancers. Avoid overexposure to the sun to prevent the following conditions.
1. Aging skin
As we grow older, our skin changes. The outer skin (epidermis) becomes thinner, paler and clearer. Age spots (also called “liver spots”) and wrinkles can show up on the face, back of the hands and arms. Lots of factors can contribute to these changes, including family history, environment and diet, but the number one factor is sun exposure.
Sun exposure also leads to overgrowth of the cells that contain pigment (color), called melanocytes. This is especially common in people with fair skin and may occur more in some families than others. Some moles occur without sun exposure, but the sun is usually the cause. Although most moles are benign (not dangerous), they can develop into cancer.
3. Dry, itchy skin
If you put a bowl of water out in the sun, it evaporates. The same thing can happen to the moisture in your skin when you’re out in the sun. This can result in dry, itchy skin. People who have a condition called xeroderma pigmentosum, in which the skin gets dry and sunburned after just a few minutes in the sun, are extremely sensitive to UV rays.
Many people associate having a tan with being in good health, but that’s not true. Your skin’s outer layer contains melanin, a pigment that protects against the UV radiation that comes from the sun. When those cells are exposed to UV rays, they multiply to try to minimize the harm, so a tan is actually a sign that the skin has already been damaged by UV rays. Doctors say there is really no safe level of tan, whether you get the tan from being outside or going to a tanning salon.
Not only can sunburns be painful, but they’re also a clear sign of skin damage. In response to UV exposure, red blood cells rush to the affected area, making the skin red and warm. The damaged skin sends messages of pain to warn you, but by the time you get that message, you might be home from the beach. Depending on your skin type, it can take six hours or even a couple of days to feel the full effects of a sunburn. Any sunburn increases your chance of developing skin cancer, especially painful sunburns that blister or peel.
6. Skin cancer
There are several different types of skin cancer, and they affect people with all different skin colors. Some are highly curable if they’re found and treated early. Others are aggressive and more difficult to treat. Exposure to UV rays increases your risk of almost all types of skin cancer, including:
- Squamous and basal cell carcinoma: “These cancers are caused by years of sun exposure and UV damage,” says Dr. McKean. “They’re most common on areas of the skin exposed to sunlight.” With early treatment in the form of surgical removal, these skin cancers are highly curable.
- Melanoma: This most dangerous kind of cancer is “highly linked to chronic sun damage and sunburns,” Dr. McKean says.
How can you protect your skin?
“You’re never too young or too old to start protecting yourself against skin conditions caused by sun damage,” says Dr. McKean. That means avoiding sun exposure, particularly between 10 a.m. and 2 p.m., when the sun’s rays are strongest. You can do this through a combination of:
- Staying indoors
- Seeking shade
- Wearing UV-protective clothing
- Applying sunscreen every time you go outside
Dr. McKean recommends sunscreen with an SPF of 30 or more every day for everyone older than 6 months. “It’s a good habit to get into because it’s hard to predict when you’re going to be out in the sun and how much exposure you’re going to have,” she says. Any FDA-approved sunscreen will work, but Dr. McKean prefers lotions or gels over sprays because it’s easier to ensure full coverage. Sunscreen should be reapplied every two hours while you’re outside, and more often when you’re swimming or sweating.
Dr. McKean also recommends getting to know your body and skin features. Check your skin regularly for changes, and be sure to look at the back of your legs using a mirror. If something looks different or new, she suggests taking a picture with your cell phone and tracking it over a few weeks.
Getting an annual skin check by your doctor and regular full-body skin self-exams should be part of your health routine if you are over 20, according to Dr. McKean, especially if you have a history of sun exposure or a family history of skin cancer. “With early detection and improved treatments, the survival rate for skin cancers has been improving.”
Now that you know how to protect yourself from sun damage, you can get out there and enjoy the outdoors — safely!