Smiling parents holding young children at beach

How to apply sunscreen correctly

May 30, 2019 | UCI Health
woman and child playing on beach

Skin cancer is the most common cancer in the United States — affecting one in five Americans — with nearly 5 million people treated annually, which is more than all other cancers combined.

Here in balmy Southern California, we work hard at shielding our skin from the sun’s harmful ultraviolet (UV) rays, which are associated with 90% of basal and squamous cells cancers, as well as more dangerous melanomas.

Too often, though, we miss protecting some important areas, says UCI Health dermatologist Natasha Mesinkovska, MD, PhD.

One of her patients, a runner in his 20s, developed a melanoma above his ear and just below the rim of the baseball cap he wore religiously to protect his head from the sun, Mesinkovska says.

Another had a melanoma on his ear.

A third developed a melanoma on her arm, perhaps caused by repeated sun exposure while cycling.

Don’t neglect to protect

This doesn’t have to happen if you are careful about protecting yourself from the sun’s UV rays, says Mesinkovska, who is also an assistant professor and director of clinical research for the UCI School of Medicine’s Department of Dermatology.

Most basal and squamous cells cancers develop on sun-exposed parts of the body, typically the face, head and hands, she says. Melanomas are most often found on the backs of men and on the legs of women.

When you’re outdoors in the direct sun or the shade, whether on a cloudy day or in bright sunlight, do not forget to apply sunscreen or cover the following most often neglected areas:

  • Back of the neck
  • Front of the neck and cleavage
  • Back of the knees
  • Ears
  • Scalp
  • Top of the feet

Don’t forget to inspect your skin

It’s important to spot skin cancers early and get treatment.

To find a skin cancer, you don’t need an invasive test such as a colonoscopy or a CT scan. But you do need to look.

“We’re fortunate that we can see the entire organ,” Mesinkovska says. “There are some nooks and crannies we can’t see into, but those areas don’t tend to grow cancers.”

She recommends examining your entire body once a month or ask a friend or significant other to take a close look.

Look for these warning signs

The three main types of skin cancer have a variety of warning signs. Here’s what to look for.

  • Any skin growth that increases in size and appears:
    • pearly
    • translucent
    • tan
    • brown
    • black
    • multicolored
  • A mole, birthmark, beauty mark or any brown spot that:
    • changes color
    • increases in size or thickness
    • changes in texture
    • is irregular in outline
    • is bigger than the size of a pencil eraser
  • A spot or sore that continues to:
    • itch
    • hurt
    • crust
    • scab
    • erode
    • bleed
  • Any open sore that doesn’t heal within two weeks

If you find any of these, consult your physician.

Most people should see a physician for a skin check once a year, Mesinkovska says. Anyone who has had a skin cancer diagnosis should get a checkup twice a year.

The bottom line

The best way to prevent skin cancer, Mesinkovska says, “is to stay out of the sun.”

Not everyone can or wants to, however.

“If you can’t stay out of the sun, be smart about it,” she says. “Use sunscreen and cover up. Put on the long-sleeve shirt, put the pants on and wear that hat with a big visor.”

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