Ask a Health Care Professional – Sun Exposure

By Diana Weber, M.D., Medical Director, Blue Cross and Blue Shield of New Mexico

Summer in New Mexico means spending time outside enjoying activities that make the state such a wonderful place to live. In moderation, sun exposure can be beneficial by enhancing bone health, improving sleep, and easing mild depression. However, even after a short period of direct exposure, the sun’s rays can become more harmful than helpful.

How long can it take for your skin to be damaged when exposed to the sun?

When your skin is exposed to the sun’s UVA and UVB rays, it can be damaged in as little as 15 minutes.  Even when it is cloudy and cool, your skin can burn. When you are at the beach or pool, sand and water reflect UV rays, increasing the risk of a burn. Here in New Mexico, we are at higher risk of sun damage and sunburns because not only is it sunny and warm, but we are at high altitude where the sun’s rays are more intense.

How long can it take for a sunburn to appear?

Unlike other types of burns, sunburn is not immediately apparent. Early symptoms include red, warm, tender, swollen skin. Ongoing burning can result in blistering, headache, fever, and fatigue, which usually start about four hours after sun exposure. These symptoms often worsen in 24-36 hours and resolve in three to five days.

Why is it important to protect your skin from the sun?

The danger of sun exposure at high altitude is not limited to painful burns. It is also the leading cause of skin cancers. Extensive lifetime sun exposure or occasional intense exposure, especially without sunscreen, increases your skin cancer risks. Artificial sources, such as sunlamps and tanning beds, also produce UV light that can damage skin.

What are the common types of skin cancer?

There are three main types of skin cancer. Their names are based on the type of cell in the layer of skin, called the epidermis, from which they originate. Basal cell carcinoma originates from basal cells, and this layer is where new skin cells grow. Squamous cell carcinoma starts in squamous cells. Melanomas derive from melanocytes, the cells that produce skin pigment called melanin.

Basal cell carcinoma is the most common type of skin cancer and the most common of all cancers worldwide. Fortunately, basal cell skin cancers are slow growing, very treatable, and seldom spread. This cancer can appear as a sore that does not heal or a firm lump that can be red, white or brown. Basal cell cancers can develop from actinic keratosis, which is a scaly patch of skin that is usually seen in areas of the body that get a lot of skin exposure. The usual treatment is often a relatively simple surgical procedure to remove the affected area. It is important to seek treatment because, although it rarely occurs, untreated basal cell cancers can spread and invade other tissues.

Squamous cell carcinoma of the skin is the second most common type of skin cancer. Squamous cells are the outermost layer of the skin. As with basal cell carcinoma, sun and UV light exposure are the most common causes of this type of cancer. Symptoms include a sore that won’t heal, a lump in the skin, or other skin changes. Squamous cell cancer grows more rapidly than basal cell cancers, and while still quite low, the risk of spread or metastasis is higher than basal cell carcinomas. The treatment is to surgically remove the lesions. There are also some topical therapies for squamous cell cancer.

Melanoma is less common than the other two cancers but is the most serious. This type of cancer originates in melanin-producing cells and usually appears as a brown, black, or red spot that has an irregular border. In fair-skinned people, it usually occurs on the trunk or legs; in dark-skinned people, it can appear on the palms, soles of the feet, or under the fingernails. The good news is that when melanoma is caught early, there is a very high likelihood of cure. The treatment is surgical removal and there are new directed therapies depending on the stage of the cancer.

What can you do to decrease your risk of skin cancer?

Many years ago, Australia initiated a campaign for sunburn prevention in response to its high rate of skin cancer: “Slip, slop, slap, seek, slide. Have fun outside but don’t get fried.”

  • Slip on a shirt: Clothes made from tightly woven fabric offer the best protection from the sun.
  • Slop on sunscreen: Cover exposed skin liberally with a broad-spectrum sunscreen with a sun protection factor (SPF) of at least 30.
    • Apply sunscreen about 30 minutes before going outside.
    • Use sunscreen even on cloudy days and when you’re in the shade.
    • Reapply every two hours — or more if you are swimming or sweating a lot.
  • Make sure to check sunscreen’s expiration date.
  • Slap on a hat with a brim all the way around that shades your face, ears and back of your neck.
  • Seek shade under an umbrella, tree, or other shelter.
  • Slide on sunnies: Sunglasses protect your eyes from UV rays and reduce the risk of cataracts.

Finally, if you notice changes in your skin, such as a new mole or lump, or if you notice that a mole has changed, bring it to the attention of your health care provider. A biopsy may be required to distinguish a benign condition from cancer. Early detection can result in treatment that leads to cure.

If you have a health question that you would like to be considered in Ask a Health Care Professional, please email [email protected]. BCBSNM will select questions that may appear. Questions will not be personally answered. The opinions expressed in this column are solely those of the author and not necessarily those of BCBSNM. This column is not intended to be a substitute for professional medical care.


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