Chronic sun exposure damages trucker's skin through glass

The striking photograph of a 69 year old truck driver in a recent New England Journal of Medicine article shows just how damaging the sun can be to your skin.

While driving a delivery truck for the last 28 years, the driver was exposed to ultraviolet A rays through the window glass on just the left side of his face. The rays penetrated the epidermis and the dermis, the first and second layers of the skin, causing a condition called unilateral dermatoheliosis.

Dermatoheliosis, also called photoaging, refers to changes in your skin due to chronic exposure to UVA and UVB rays. The result is a gradual thickening and deep wrinkling of the skin.

According to the American Cancer Society (ACS), there are three main types of ultraviolet radiation. UVA rays can cause cells to age and damage the skin's DNA. They are linked to long term damage like wrinkles and can lead to some skin cancers.

UVB rays are the main cause of sunburns and are believed to cause most skin cancer. UVC rays are not present in sunlight and and not typically linked to skin cancer.

The Skin Cancer Foundation says UVA rays are less intense than UVB rays and up to 50 times more prevalent. They also penetrate the skin more deeply and are a major factor in skin aging and wrinkling.

The foundation's website says, "UVA is the dominant tanning ray, and we now know that tanning, whether outdoors or in a salon, causes cumulative damage over time. A tan results from injury to the skin's DNA; the skin darkens in an imperfect attempt to prevent further DNA damage. These imperfections, or mutations, can lead to skin cancer."

But, the foundation says, "UVB rays do not significantly penetrate glass."

Dr. Martin Weinstock, a professor of Dermatology at Brown University, and Chair of the American Cancer Society's skin cancer advisory committee, says UVB rays don't come through car windows unless they are open, and that even though you can get UVA rays through a closed window, the average person should not be overly concerned.

"In general there is not a huge amount of concern in people inside a car with the windows shut."

Weinstock's advice to consumers is to use a broad spectrum sun screen that protects against both UVA and UVB rays.  "Using sunscreen SPF 30 or greater is the simplest bottom line.  You gotta apply it whenever you're out for maximum protection.  You just have to apply it consistently and you have to reapply periodically, every few hours."

The ACS also recommends protecting yourself from UV rays by covering up, wearing a hat and sunglasses to block the rays and by limiting direct sun exposure in the middle of the day.  UV rays are usually strongest between 10 a.m. and 4 p.m.