Woman at the beach with an exclamation point made of sunscreen on her back

During skin cancer awareness month, LLU dermatologists Conroy Chow, MD, and Harry Dao, MD, bring to light certain risk factors for skin cancer that may not necessarily be top of mind.

“We see a lot of patients for routine skin exams, and there are many habits that my patients may not have considered that will put them at increased risk for skin cancer,” says Dao, chair of dermatology for Loma Linda University Health.

Risk factors for skin cancer— lifestyle, health status, genetics, occupation, geographic location, and more — are difficult to isolate and quantify because they work in tandem, combining to create varying levels of risk for skin cancer across individuals. Chow and Dao therefore recommend taking the risk factors that pertain to you into account to learn how to best protect yourself.

Harmful habits

Generally speaking, people at early stages in their lives spend a lot of time outdoors. In fact, studies report about 80% of the ultraviolet (UV) light people are exposed to in their entire lifetimes occurs before they turn 18 years old. “Think about when we had time to go on summer vacation,” Chow says.

Children, teenagers, and young adults’ time spent in the sunshine combined with their lower likelihood of using sun protection create a dangerous circumstance for developing skin cancer down the line, according to the CDC. Repercussions of the UV exposure, resulting in increased risks of skin cancer, do not typically present until decades later, he says, so adopting the habit of applying sunscreen and wearing sun-protective clothing early on in life is crucial.

“The more UV light our skin cells get, the more likely it will lead to DNA damage and mutations that could lead to skin cancers,” he says. “The changes do not happen like an on-and-off switch — it’s oftentimes a progression of changes.”

Furthermore, visiting tanning salons boosts UV exposure to an unnatural and harmful degree. Chow urges anyone engaged in the habit to cease doing so because of the serious risks they pose for skin cancer.

Balancing nutrients, medications with protective measures

Many people are deficient in vitamin D, a nutrient that helps the body use calcium and phosphorus to strengthen bones and teeth. Though exposing skin to sunshine helps the body create vitamin D, people should not rely solely on sun exposure to acquire vitamin D because the UV exposure from sunshine heightens the risk of skin damage and subsequent skin cancer. Taking supplements for vitamin D helps the body gain the important nutrient, according to the American Cancer Society, as well as eating foods such as fish, egg yolks, mushrooms, and certain dairy products.

Recognizing that time spent outdoors can be beneficial for bone health and mental health, though, Chow and Dao support enjoying the sunshine safely by protecting oneself with sunscreen and re-applying every couple of hours.

Additionally, certain medications — such as doxycycline for acne or hydrochlorothiazide for blood pressure —make skin more sun-sensitive, increasing the likelihood of developing a sunburn from UV light exposure and thus increasing skin cancer risk. Dao and Chow counsel to speak with a doctor about any medications you take that could heighten skin sensitivity to sun and protecting yourself with sunscreen and sun-protective clothes accordingly.

Omnipresent chance of sunburns, insufficient SPF protection

Spending time shore-side on a sunny day without sun protection places you at risk of harmful UV exposure and skin cancer — lesser known is the fact that the same may occur on a cloudy day, or even indoors.

Though clouds do block some of the UV light from sunshine, you are still at risk of getting sunburnt if you do not apply sunscreen, Chow says. Believing they are completely protected by cloud coverage, some people are inclined to prolong their stay outdoors without sunscreen, he says. Occasionally, the unsuspecting person ends up with a sunburn at the end of their day — same goes for staying indoors. UV light is not filtered out of many types of window glass, placing those who spend the majority of their day by a window — such as airline pilots — at risk of UV exposure.

In every scenario, Chow and Dao advise applying daily sunscreen with a sun protection factor (SPF) of 30 or more, because the number 30 is actually an overstatement when it comes to everyday use. Realistically, a sufficient amount of sunscreen to achieve a SPF 30 level of protection is not routinely applied successfully, leading to a false sense of security. Lab studies test SPF effectiveness by applying sunscreen to leave a white hue on the skin. Yet in everyday usage of SPF, people do not usually apply it to the point that the white hue of the cream remains on the skin — they apply a third to a half of what was tested in the lab.

Never say never

Though exposure to UV light is the top risk factor for developing skin cancer by far, Dao says he has seen skin cancers develop in places where a patient may never have experienced an ounce of sunshine exposure — this is where factors out of our control come into play.

“I tell my patients, ‘you can still develop skin cancer in areas of the body that don’t typically get much sun,’” Chow says. “The risk is of course lower, but even when there is no environmental cause, it could be a genetic, or ‘bad luck,’ mutation in the body.”

On a similar note, while people with darker skin pigmentation are generally at lower risks of sunburns, Chow says it does not by any means disqualify them from developing skin cancer.

Regardless of skin tone or level of UV exposure, Chow and Dao stress the significance of remaining attentive to the features on your skin and following up on any suspicious appearances or changes with a physician. For some, this may manifest on the skin as a supposed pimple that spontaneously and repeatedly bleeds, a freckle that has grown disproportionately in a short period of time, or a mole that has changed colors.

“If you miss it or brush it off and it happens to be skin cancer, this leads to the potential for major surgeries and adjunctive therapies like chemotherapy, immunotherapy, and radiation,” Dao says. “We offer full body skin exams and detect any suspicious lesions as soon as possible.” When in any doubt regarding a lesion, he recommends erring on the side of caution and getting it evaluated for the sake of your health.


Loma Linda University Health has specialists who can help you decipher the clues your body may or may not be revealing and join you on your journey back to health. Partner with a healthcare provider today to help answer all of your questions. To learn more, visit the skin cancer webpage or call 800-782-2623.