How Bad Is It Really to Skip Sunscreen if You 'Never' Burn?

Some people turn red if they're under the sun without protection for even a short period of time, while others seem to rarely, if ever, burn. Maybe you have a dark complexion or an olive tone that gets more deeply tanned instead of lobster-like.

如果您的皮肤永远不会脆弱，您可能会暂时跳过SPF。2015年7月的研究美国皮肤科学院学报发现，在阳光下一个小时后不燃烧的人中，只有6％的男性和25％的女性经常穿着遮阳板。研究人员怀疑是因为他们不会认为自己易受阳光损坏。

那么，如果你从未被过度煮过，可以在防晒霜上传递通行证吗？或者紫外线辐射仍然可以达到损失，无论什么样的皮肤类型？我们要求Derms解释。（SPOILER ALERT：太阳保护对每个人都非常重要！）

这一切都归结为黑色素, a natural skin pigment produced in a type of skin cell called melanocytes.

"Melanin's role is to protect the DNA content of our skin cells from the sun," says dermatologistHeather Woolery-Lloyd, MD, director of the Skin of Color Division at the University of Miami Department of Dermatology and spokesperson for theSkin of Color Society. "When you look at skin cells under a microscope, melanin is like a little umbrella that sits right above the nucleus of the skin cell, closest to the sun."

This melanin umbrella partially blocks UV radiation from sunlight. The more melanin in your body, the darker your skin is, and the more natural sun coverage you have. According to a January 2016 study in the中国临床和美学皮肤病学杂志，黑色皮肤提供平均当量SPF为13.4。

"If UV radiation damages the contents of your skin cells beyond repair, your body begins the process of apoptosis, where your skin cells essentially kill themselves — that's what a sunburn is."

Once sunlight penetrates this melanin umbrella and reaches the keratinocytes, which are the outermost skin cells, UV radiation begins to ravage the cell's DNA.

“如果紫外线辐射会损害皮肤细胞的内容，你的身体开始细胞凋亡的过程，你的皮肤细胞基本上杀死自己 - 这就是晒伤，”洛伊德劳埃德博士说。“由于受伤的皮肤细胞不能挽救，他们死了，脱掉了，然后用新的细胞开始。”

患有公平的皮肤的人没有大量的黑色素，这意味着它们更容易受到紫外线辐射的影响。尽管如此，如果你有黑色或棕色的皮肤，那并不意味着你离开了钩子。

“你的皮肤越暗，你可以忍受的紫外线辐射，但它不是无限的，”羊毛劳埃德博士说。“甚至是肤色最黑暗的人，歌手密封的颜色，可以在一定量的阳光暴露后获得起泡的晒伤。”

A 2012 report from theCenters for Disease Control and Prevention(CDC) found that 11 percent of Black Americans and 35 percent of Hispanics had at least one sunburn in the past year.

Moreover, without the telltale redness, some dark-skinned people might not even realize that they have sunburn. (Per theCDC, other signs include sensitivity, swelling, blisters, headache, nausea, fatigue, flaking and skin that is warm to the touch.)

And you should know that, even if you didn't burn, a tan is still indicative of genetic damage to yourskin cells. According to the皮肤癌基础, there is no such thing as a safe or healthy tan.

It's true that fair-skinned people are more likely to develop skin cancer than people with black or brown skin, thanks to their lower levels of protective melanin. And a 2016 study in the亚太地区癌症预防杂志revealed that there is no clear link between sun exposure and squamous cell cancer or melanoma amongst people of color.

But the study also confirmed that repeated DNA damage from unprotected exposure to UV rays heightens the incidence of basal cell cancer for all skin types. In people of color, 90 percent of basal cell carcinomas are found on the head or neck, where the sun's rays hit. BIPOC who live in sunnier climates are also more likely to develop basal cell cancer than those located farther north of the equator.

更重要的是，黑皮肤的人仍然可以发展鳞状细胞癌或黑色素瘤，尽管发病率要低得多，病变通常在阳光不达到的区域开发。鳞状细胞癌通常在臀部，腿部和脚上看到，而黑色素瘤在棕榈树中呈现在掌上型，脚趾或脚底。

因为癌症通常位于不接触太阳的路易区域，因此它们往往不会被忽视或误诊。2019年7月从中学习CDCfound that survival rates for people of color with melanoma are significantly lower than for people with white skin, likely due to delays in diagnosis.

Higher melanin levels offer enhanced sun protection but also make you more prone to hyperpigmentation.

"The darker your skin, the more reactive your melanocytes are," Dr. Woolery-Lloyd says. "Sun exposure triggers melanocytes to turn on and produce more melanin."

As a result, chronic unprotected sun exposure often leads to uneven skin tone, like freckles and darker splotches on your cheeks.

“你的皮肤越深，你可以容忍的紫外线辐射越多，但它不是无限的。甚至有最黑暗的肤色的人也可以在一定量的阳光暴露之后获得起泡的晒伤。”

People with more melanin are also at greater risk for melasma, a skin disorder resulting in a blotchy brown complexion.

“人们与肝斑等皮肤变色a high incidence of low self-confidence, which interferes with their quality of life," says Santa Monica-based dermatologistTanya Kormeili，MD, clinical professor of dermatology at UCLA's David Geffen School of Medicine. "Melasma gets worse in the sun, and using SPF is a huge part of preventing and correcting it."

First, the good news: If you have dark skin, you won't develop as many fine lines and wrinkles as people with light skin. "Because melanin provides protection against UV radiation, it is less likely to penetrate the dermis and damage your collagen and elastin," Dr. Woolery-Lloyd says.

Now here's the hitch: Remember those ultra-reactive melanocytes that cause hyperpigmentation when you spend time unprotected in the sun? According to a September 2017 study in theMaedica临床医学杂志, mottled skin color (like freckles, dark spots and splotches) can make you look up to 20 years older than you actually are.

“一些临床研究发现，不均匀的肤色更暗示比皱纹更暗示，”洛伊德劳埃德博士说。“研究人员Photoshop的图片照片将乌鸦的脚或棕色斑点添加到他们的脸上 - 添加皱纹的图片被认为是比那些棕色斑点的照片。”

Keep in mind that the amount of melanin in your skin isn't the only factor at play when it comes to photoaging. "Your risk of DNA damage is 20 percent genetic and 80 percent environmental — including sun exposure, diet,exposure to pollutionand smoking," Dr. Woolery-Lloyd says.

她指出,她有时看到老patients with very fair skin who look really young, even though they used to bake in the sun. "They might have a more effective DNA repair system that is protecting them," Dr. Woolery Lloyd says. "Whereas other people have wrinkling disproportionate to their sun exposure, just because they have a genetic predisposition to it."

Plus, some drugs — like tretinoin, blood pressure meds containing hydrochlorothiazide and certain migraine pills — can also up your risk of sun damage. (You can find a complete list at the皮肤癌基础.)

"These medications may suppress part of the skin's DNA repair mechanism or create a phototoxic substance in the skin," Dr. Woolery-Llyod says. If you're taking anything on the list, sunscreen is essential.

多年来一直是备用建议：无论您的肤色，都能佩戴具有至少30个的广谱防晒霜。

但是当您这些天时，您可以寻找阳光保护时有其他东西。矿物（或物理）防晒霜有很多嗡嗡声，坐在皮肤上，创造一个偏转紫外线的屏障。另一方面，化学防晒霜，通过在损伤皮肤之前通过吸收光线来工作。研究表明，前者更有效和更健康。

“化学防晒霜更快地分解并不提供与身体防晒霜一样多的保护，”Kormeili博士说。洛伊德劳埃德博士补充说，与化学种类相比，使用矿物防晒剂时，敏感皮肤的人们往往具有较少的刺激。

In addition, a January 2020 study inJAMAfound that chemical sunscreens are absorbed into the bloodstream — even after a single use — where they can remain for extended periods of time.

"They are also estrogen mimickers, so when you get large doses of it your body thinks it has extra estrogen," Dr. Kormeili says. "The chemicals in these sunscreens have been found inbreast cancer组织和使用大量的人可能会遭受内分泌问题。“

The downside to mineral sunscreens, which contain zinc or titanium, is that the thick, white cream can lend a gray cast to darker skin. "To avoid looking like you have yogurt on your face, try a tinted physical sunscreen that matches your skin tone," Dr. Kormeili says.

"From a cosmetic standpoint, it's pretty bad," Dr. Woolery-Lloyd says. "Even people who don't burn will still get photoaging from chronic unprotected sun exposure, so if you're concerned about fine lines, wrinkles or uneven tone, your skin won't look the way you want it to look when you're in your 40s or older."

Applying a little SPF-infused face cream every day isn't a lot to ask, and the payoff is huge.

As for skin cancer: "If you have olive or black skin, your risk is lower, but it's not zero," Dr. Woolery-Lloyd says. "I have lots of patients with dark skin who still get skin cancer."

Do you really want to take that chance? Thought not. Now crack open that bottle of sunscreen and get your SPF on!