Body Skin

baa · dee –skin

The state of your body skin is determined by hundreds of factors unique to each individual, from genetics to diet.

What is body skin and how is it different from face skin?

Body skin isn’t that different from face skin, truth be told. They both serve the same purpose: To protect the body from threats like the sun, temperature extremes, and bacteria, to help regulate body temperature, store water and nutrients, and to let you feel, quite literally.1 The biggest difference between face and body skin is the skin’s thickness. Face skin is generally thinner than body skin, though body skin ranges in thickness.2 (For example, the skin on your elbows is thinner than the skin on your palms. Eyelid skin is the thinnest of all.)3 Other factors come into play: Older people usually have thinner skin than younger people,4 men tend to have thicker skin than women5, and certain medical conditions can also affect the skin’s thickness and texture.

In those areas where the skin is thinner—on the face, especially around the eyes, and the neck—it’s more susceptible to outside threats (the sun, germs, but even the ingredients in some skincare products). “Skin on the face is typically more sensitive than skin on the body,” notes Dr. Erica Stevens, a board-certified dermatologist at Westlake Dermatology in Austin, Texas. “Some areas on the face actually have thinner skin, particularly around the eyelids, so you have to be careful about the application of topical products there.” Face skin is also more exposed. The fact that body skin tends to be covered by clothes adds another layer of protection against the elements.


What different types of skin do we have on our bodies?


Skin is categorized by where it is on the body, and while the structure of the skin is consistent across the whole body the geography can be a little different.6 Some areas have more hair follicles than others (like, well, the scalp), more protective fatty tissue underneath, some areas produce more oil, and some have more sweat glands (...armpits). The difference in the skin’s properties across the body usually makes sense for what that part of the body does; for example, the skin on the palms of the hands is thick, ready to grab, touch, and perform a lot of work.


How can I treat sensitive body skin?


Talk to your dermatologist for a specific treatment plan for your skin’s sensitivity, which may be a result of an allergy, medical condition, or dry, dehydrated skin. Sensitive skin might be red, itchy, or prone to breakouts, and each of those requires a different treatment plan. But generally, washing with gentle, unscented soaps, and bathing/showering in not-too-hot water is the first step in sensitive skin care. For patients with dry, sensitive skin, Dr. Hope Mitchell, a board-certified dermatologist in Perrysburg, Ohio, points to the shower: “I believe that patients need to be properly educated as to the products that they’re using and the duration of time that they’re in the shower,” she says, adding that the time should be 5-to-10 minutes, tops. “The recommendation always is to use milder products. I often tell my patients to look for the words ‘pH balancing,’ ‘gentle,’ ‘hydrating,’ those should be buzzwords when picking a product.”

Moisturizing helps maintain hydrated, healthy skin (while avoiding heavily perfumed products and don’t even think about glitter). Sensitive skin can also flare from environmental factors, like laundry detergent, certain fabrics—spandex leggings that cling to the skin or scratchy wool—extreme weather, reaction to medications, etc.

Switching to an unscented detergent, wearing loose, breathable fabrics, and turning on a few humidifiers could all help treat sensitive skin issues.

A doctor can help pinpoint the cause and treatment of skin sensitivity; it might even just be genetic.

How does my biology affect my skin?

There’s a reason it can be frustrating to find the perfect solution to a skin issue you’re experiencing, and it’s because your skin is absolutely unique to your body and genetic code. But the structure of the skin is consistent: underneath the top layer of skin (the epidermis), other layers of the skin are producing hairs, collagen, elastin, vitamins, sebum (oil), and water, and contain fat cells and connective tissue that protect the organs underneath and give us literal cushion.7 As the body ages, it produces less of some of those substances like collagen and elastin8 (which is why wrinkles happen); hormone activity affects the skin, which is why pregnant women experience a range of skin changes; ethnicity and skin tone play a huge role in common skin issues (the biggest example: lighter tones are more vulnerable to skin cancer, while darker tones are more likely to hyperpigment);9 and genetics connect many skin conditions, like dry skin, throughout generations. From the outside, the skin is just sitting there passively as we forget to apply sunscreen that third hour on the beach. But in fact it’s a host of a lot of activity that’s all happening below the surface.


Genetics


“Genetics definitely play a role with your skin,” says Dr. Stevens. “For example, if you have fairer skin and light eyes, you will be at higher risk for skin cancer than someone with more richly pigmented skin.” (However, that leads to a common misconception that people with skin of color can’t get skin cancer—they can, and it often goes undetected due to this fallacy, which is why they’re in fact more likely to die because of it.)10 Genetics play a role in skin tone and skin type—perhaps you and a parent share similar oily skin, or both battled teenage acne11—and can also indicate how the skin ages, which is why there’s that old cliché about seeing how you’ll age by looking at your parents.12 (But hey, the sun plays a huge role in that too.)13 Studies have found genetic links to common skin conditions like acne and keratosis pilaris, as well as lesser common conditions like Albinism and a range of genetic skin diseases.


Age


The body begins to produce less collagen at around age 45,14 which is why skin gets thinner as we age,15 the extent to which can depend on ethnicity and genetics. In fact, the body produces less of everything that contributes to healthy skin, not just collagen but antioxidants, and sebum, the self-produced oil that helps your skin retain moisture. This is why older skin tends to be drier. Aging skin loses elasticity—a euphemism for sagging skin. Cell turnover at the surface of the skin slows down, which can then slow the process of wound healing (perhaps you or an older person you know bruises easily—this is why).16


Pregnancy


90 percent of pregnant women report significant skin changes, from acne to stretch marks.17 It’s almost inevitable. Hormone levels change dramatically during pregnancy in order to stimulate milk production, provide nutrition to the fetus, and generally prepare the body to give birth. And hormones directly affect the skin. Certain hormones set off sebum (oil) production, which is why pregnancy acne is so common.18 Pregnancy is also largely associated with melasma, splotches of hyperpigmented skin, usually on the face/neck, called “the mask of pregnancy.” Skin changes during pregnancy might also include the appearance of spider or varicose veins, linea nigra (a dark vertical line on the stomach), thicker (or thinning) hair and faster nail growth, and pregnancy-specific rashes. These skin conditions usually end after giving birth, but some may take months or years to fade, like stretch marks. Because of the way skin absorbs ingredients in skincare, some treatments, like high concentrations of retinoids, are to be avoided during pregnancy because there’s been a lack of research around their effects19—talk to your doctor to double-check any products you’re concerned about.


Hormones


Think of hormones as mid-level managers in the body. There’s a lot of them, and they’re constantly being produced in order to tell the body how to function. Without getting into the names of specific hormones, when it comes to the skin, a big influence hormones have is on sebum production, that level of oil produced on the skin that can determine whether your skin is oily, acne-prone, or dry. Hormones spark hair and nail growth; influence the distribution of melanin,20 the pigment of the skin; while stress hormones can trigger flares in several skin conditions, including acne.21 “Hormones can affect many types of skin conditions,” notes Dr. Stevens, “including acne (worsens in teenage years or around the menstrual cycle for many women) and melasma (hyperpigmentation on the face that can worsen with pregnancy and contraception).” This is also why people taking birth control, steroids, and hormone therapy medications might see changes in their skin.


Disease


Diseases can affect the skin in hundreds of ways, whether as a result of the disease spreading in the body or the side effects of the surgeries and medications used to treat them. For example, the American Academy of Dermatology points out 12 “warning signs” on the skin that are associated with diabetes, including dry, itchy skin or thickened, velvety folds of skin called acanthosis nigricans.22 Cancer treatment, like chemotherapy, can severely dry the skin, while radiation can cause blisters and rashes.23 Hepatitis B, which affects hundreds of millions of people a year, is associated with a bumpy skin rash.24 If you’re experiencing a rash or skin reaction that’s new and worries you, see a dermatologist or your primary care physician as it could be an allergic reaction, or a sign of a yet-undiagnosed health condition.


pH


In case you haven’t taken a chemistry class in a few years, a quick recap: pH is the measure of how acidic or basic a substance is on a range of 0-14 (so 7 is “neutral”). “The skin’s normal pH will range from 4.5 to 5.5,” explains Dr. Hope Mitchell, a board-certified dermatologist in Perrysburg, Ohio. “It works best with light acidity. If the pH is lower than 4.5 to 5.5, let’s say it’s a 4.0, 3.5, that’s when we might start to see more signs and symptoms of dry skin and itching or flaking or peeling.” If you’ve ever heard the term “acid mantle,” that’s referring to the thin layer on the surface of the skin that exists to protect against outside threats like pollution, allergens, and bacteria.25 Disrupting it with harsh, alkaline cleansers leads to stripping the skin, irritating and drying it out.26 It’s becoming more and more popular to see “pH-balancing”, or even pH measures, on skincare packages, usually somewhere close to the skin’s natural pH, around 5.5.27

How does my skin tone/ethnicity affect my skin?

Unfortunately, for much of history, dermatology studies and medical diagnosis photos have favored white skin28 to the detriment of those with skin of color who may have skin diseases—including lethal melanoma—that go undiagnosed longer than those with paler skin.29 (The field itself has a lack of board-certified dermatologists of color, which has led to new initiatives to diversify the specialty.)30 Awareness of this bias is now prevalent, so there’s hope that future skin research will be more comprehensive, inclusive, and consequential.

Skin tone is determined by how much melanin is produced in the skin. The more melanin, the darker the skin tone. The most consequential difference between skin tone and skin health is how much more susceptible those with lighter skin tones are to melanoma/skin cancer: White skin is around 70 percent more likely to get melanoma than Black skin.31 Melanin filters UV rays like built-in sunscreen. But the sun’s rays can still cause dark spots, and skin cancer in Black patients, which is why dermatologists recommend everyone, no matter what skin tone, wear sunscreen. Darker skin tones are more inclined to hyperpigmentation (which could come from acne scars or sun spots) than lighter skin tones.32

Ethnicity can be an indicator of certain skin traits or conditions: how big your pores are (one study found that Brazilian people have larger pores, Asian people have smaller pores),33 likelihood of ingrown hairs (Black hair that’s naturally coarse and curly is more inclined to curl back into the skin),34 or rosacea (more common to occur in white skin),35 or hyperpigmentation (darker skin tones are more inclined to hyperpigment).36

That’s a very short list of the many skin conditions that are experienced by one ethnicity more than others, which is why dermatologists are constantly repeating there’s no “one size fits all” for skincare.


Are acids/AHAs harmful to darker skin tones?


“Topical acids can be helpful for certain conditions, no matter the skin type,” says Dr. Erica Stevens. “Glycolic acid is a type of alpha hydroxy acid and when used appropriately can be beneficial for skin brightening. Salicylic acid is a beta hydroxy acid and can be useful for people with acne-prone skin in reducing the number of whiteheads and blackheads.”

Some acids are more intense than others, and their potency is often indicated on the product container in a percentage (glycolic tends to be a gentler acid, though). People of all skin types should avoid overuse of these acids because they can be so effective that they shed too much of the skin’s acid mantle and cause dry, irritated, or inflamed skin that leads to dark spots/hyperpigmentation. Dark skin tones tends to experience more hyperpigmentation than lighter tones, so that’s a possible heightened risk when using AHAs/acids,37 but dermatologists often recommend easing into these acids once a week, and following up with sunscreen, to avoid any negative reaction.38 Because skincare research has had a historic white bias, the effect of different ingredients on darker skin tones hasn’t been robustly studied, so it can be frustrating to find a direct answer to this question.


Are darker skin tones differently affected by dark marks and stretch marks?


Dark marks, also called post-inflammatory hyperpigmentation, appear more often in people with darker skin tones because their body produces more melanin than those with lighter skin tones at a base level.39 Dark marks and stretch marks don’t harm the skin, they just appear different across skin tones. One study found that Black women have more severe stretch marks than white women,40 and that stretch marks appear more prominent in darker skin tones.41 Stretch marks may appear red, brown, purple, white, or even blue, depending on skin tone.42


How do skin discolorations vary among different skin tones?


In lighter skin tones, where the body doesn’t produce as much melanin, skin discoloration might show up pink or red when it’s injured and inflamed, where darker tones might turn a range of brown, burgundy, or purple, depending on the skin condition. A common type of skin discoloration is hyperpigmentation, when skin darkens to a tone deeper than its base color. Dr. William Kwan, a board-certified dermatologist in San Francisco and expert in skin of color, sees it often: “I see more hyperpigmentation in darker skin just because, myself included, we have more skin pigmentation, more melanin pigment,” he says. Post-inflammatory hyperpigmentation means skin that’s darkened as a result of injury, and it is more common among darker skin tones.43 One example of that is that skin of color has been found to experience more acne scarring than white skin.44

How does my environment affect my skin?

Skin is constantly changing—turning over new cells on the surface, and responding to changes in the external environment and in the body itself.45 Cycles in the weather where you live are a reason why the skin might become oily, sun-damaged, or dry. Environmental factors that could affect the skin also include pollution in the air and even your indoor environment (sitting in harsh air-conditioning all day).


Pollution


Air pollution affects the skin—and the whole body—when those fumes are inhaled and make their way through the body’s various systems, or when pollutants enter the skin through hair follicles/pores. Air pollution is a blanket term that includes any airborne irritant, from mold to carbon monoxide to methane. And while areas like cities have higher pollution levels, the World Health Organization estimates that 90 percent of the world’s population experiences daily pollution in some form.46

Inside the body, those pollutants can lower the level of antioxidants like Vitamin C and E, and degrade collagen production, leading to dry skin, loss in elasticity, and premature aging. Studies have found that air pollutants can worsen the symptoms of skin conditions like eczema and psoriasis47 and cause increased dark spots.48 Wearing SPF, regularly cleansing, and using products with antioxidants are the general rules of thumb to combat the effects of pollution on the skin, a topic that’s still very much being studied.49


Weather and Humidity


It’s common to experience dry skin in the winter, due to a combination of the outside weather and the dry, heated air cranking inside. In drier climates, water on the surface of the skin that keeps it hydrated evaporates off faster (if you’ve never thought about your skin evaporating, there’s a first time for everything).50 A walk on a frigid, windy day might cause the skin to feel dry and itchy, or look inflamed or even chapped.

Humid climates help the skin maintain its moisture, but that humidity may also be so high that oily-prone skin appears shinier. People who live in humid climates might not slather themselves in moisturizer day and night like people who live in colder, drier places. “I can definitely see why some people in the summer don’t use a body lotion,” says Dr. Hope Mitchell, a board-certified dermatologist in Perrysburg, Ohio, “because we have a lot of humidity that adds water to the skin. On those hot summer 90° days, we may not need it.” However, all that moisture in the air can make people more susceptible to fungal skin infections.


Heat and A/C


Artificial air blowing through a vent, whether it’s hot or cold, creates a low-humidity environment, which can cause dry skin. A humidifier can help counter that, but a change in skincare routine might also help (a thicker moisturizer or cream, or moisturizing more than once or twice a day; this all depends on the person). Air conditioners and heaters can also spread bacteria and dust throughout a space when poorly maintained, potentially triggering allergies and infections, but they also have filters that keep outdoor pollutants from coming inside, which is a good thing.51 Generally, the most common adverse effect heat and A/C have on the skin is accentuated dryness.


Sun Exposure


You could write a whole book on the sun’s effect on the skin, and a few people have. “Sun exposure damages skin cells, which leads not only to aging but can lead to the development of precancers and skin cancer later in life,” says Dr. Erica Stevens. “This is why dermatologists recommend SPF 30+ daily to protect against that damage from sunlight.” Sun exposure is linked most importantly to skin cancer,52 but signs of aging like wrinkles,53 sun spots, hyperpigmentation, melasma, and more.

How do habits affect my skin?

Acne, pore size, melanin, wrinkles—so much of skin health is determined by genetics. And when it comes to signs of aging, so much is determined by a lifetime of damage from the sun.54 But day-to-day habits can affect the skin too, like sleeping in makeup, which mixes with the skin’s natural oils at night and causes an oil-and-bacteria basecamp for a breakout. Almost every facet of your life has a link back to the health of your skin, whether you work in an office with dry, circulated air-conditioning or outside, in full view of the sun, exposed to pollution, wind, and dirt. Exercise, diet, sleep, stress, smoking, and drinking all affect the skin, some in good ways (exercise, sleep) and others in harmful ways (smoking).


Diet


The link between diet and skin health is still being studied, and much of what’s been studied is controversial, contradictory, and confusing. According to the American Academy of Dermatology, eating a diet that’s good for your overall health is probably the best way to support skin health too.55 You won’t be surprised to hear that they’re referring to fruits, vegetables, whole grains, and healthy fats.

“There is a small amount of scientific evidence that diets high in sugary/processed foods and dairy products may worsen acne,”56 notes Dr. Erica Stevens. There’s also a possible—again, possible—connection between diet and skin aging that suggests a diet rich in antioxidants (think fresh fruits and vegetables) can delay signs of skin aging, like wrinkles and loss of elasticity.57 Antioxidants is a category that includes vitamins C and E, which protect and repair the skin from sun damage like brown spots, and promote collagen growth. The body naturally produces those, but it slows production as we age, so returning those nutrients to the body may also reach them on the skin level.

Certain foods may trigger skin conditions from acne to psoriasis, completely depending on the person.58 So much of what’s going on with skin is determined by genetics, one person’s experience cutting out gluten may be the exact opposite of another’s. If you’re noticing skin flare-ups after eating specific foods, talk to your dermatologist to investigate further.


Exercise


Exercise is generally good for the skin. It gets the blood pumping throughout the whole body and that blood carries nutrients the skin needs for overall health, functionality, and that healthy-glow-look.59 Exercise also helps mediate stress, and because stress can be an oil and acne-trigger for the skin, exercise can indirectly keep breakouts at bay.60

On the other hand, working up a sweat, and wiping that same sweat towel on your face for a workout, can cause a mess of bacteria, oil, and dirt on your skin that may lead to acne, so it’s important to shower, or at least wash your face, immediately after working out.61 If you’re a swimmer, the chlorine or salt in the pool can be drying to skin and require a more rigorous moisturizing routine. Exercise can trigger psoriasis or eczema in those who are prone to those skin conditions, but it can be mitigated with moisturizer and the flare might be temporary—talk to your dermatologist if you’re noticing any concerning skin issues after you exercise. Ideally you’ll want to find a solution that keeps you exercising, because the long-term benefits for your overall health are so great.

It almost goes without saying, but it’s too important to leave unsaid: If you’re exercising outside, wear sunscreen. The effect of the sun on the skin is greater than any other factor, and sunscreen is the easiest way to delay damage from those rays, from a few brown spots to full-blown melanoma.62


Alcohol and Smoking


If the much-studied link to lung cancer isn’t enough to show that smoking isn’t good for you,63 studies have found it’s no friend to your skin either.64 “Smoking can also increase the appearance of aging, wrinkles, and fine lines in the skin,” says Dr. Erica Stevens. Nicotine decreases blood flow,65 which keeps oxygen and nutrients from reaching the skin, while the repetition of pursing the lips while smoking also contributes to wrinkles.66

Heavy alcohol use—defined as eight or more drinks a week—can contribute to skin aging,67 lines, visible blood vessels, and puffy under-eyes. Alcohol is generally dehydrating, and can cause redness/inflammation in some people.


Current Skincare Routine


Your skincare routine can affect the skin underneath in myriad ways. Maybe you read a ton of articles recently recommending “double cleansing,”68 which was soon followed by a ton of articles about repairing the skin barrier (damaged from too much cleansing).69 By over-cleansing—and the same goes for over-exfoliating—you risk stripping so much of the skin’s self-produced oils it dries out, or reacts by over-producing oil and causing breakouts.70 It’s skincare Catch-22.

A routine that includes layering on thick creams and oils could risk clogging the pores and causing breakouts. “If you think they'll clog your pores, it probably will,” says Dr. Tiffany Libby, a board-certified dermatologist at Brown Dermatology. On the other hand, a lack of skincare routine, especially twice-daily cleansing, can cause a buildup of oil, dirt, and bacteria that leads to breakouts too.

Whether you love skincare and are excited to try new products, or searching for the perfect combination of products to solve an issue you have, it’s easy to accumulate a skincare routine with what feels like 15 products. And at what point do you know which of those are helping, hurting, or canceling each other out? “Three to four [products] is a goal for me,” says Dr. Libby. “But it's hard for the individual to pick those best three to four for themselves.” If you’re overwhelmed with choice and unsure which cleanser, serum, moisturizer, and sunscreen is best for your skin, talk to your dermatologist about it to see what they recommend. They’re going to have better suggestions than the salesperson in the cosmetics aisle trying to sell you a day eye cream and a night eye cream.


Sleep


As it sleeps, the body regenerates nutrients that were expelled during the day. So while getting eight-ish hours of sleep a night is good for overall health, from the body to the brain, it’s good for the skin, too. In studies, people who get the recommended amount of sleep tend to report feeling better about their skin appearance than those who didn’t get enough sleep.71 One study linked chronic low-quality sleep with more signs of skin aging;72 another linked low-quality sleep with more severe acne.73 Sleep can be dehydrating (think about how much water you’re not drinking for eight hours straight), and sleeping on dirty sheets can also contribute to breakouts. And perhaps you know from experience that sleep deprivation can cause dark under-eye circles, droopy eyelids, and a dull complexion, which happens because blood flow slows down as the body goes into low-battery mode.74

Citations

1Structural and biophysical characteristics of human skin in maintaining proper epidermal barrier function by Magdalena Boer et al. Postepy Dermatol Alergol.
2Epidermal thickness at different body sites: relationship to age, gender, pigmentation, blood content, skin type and smoking habits by Jane Sandby-Møller, Thomas Poulsen, and Hans Christian Wulf. Acta Derm Venereol.
3A comprehensive examination of topographic thickness of skin in the human face by Karan Chopra et al. Aesthet Surg J.
4Skin anti-aging strategies by Ruta Ganceviciene et al. Dermatoendocrinol.
5,15Male versus female skin: What dermatologists and cosmeticians should know by S. Rahrovan, MD et al. Int J Womens Dermatol.
6,7Anatomy, Skin (Integument), Epidermis by Hani Yousef et al. Epidermis.
8,12Genetics and skin aging by Evgenia Makrantonaki et al. Dermatoendocrinol.
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10,32Skin Cancer Concerns in People of Color: Risk Factors and Prevention by Alpana K Gupta et al. Asian Pac J Cancer Prev.
11What does acne genetics teach us about disease pathogenesis? by J E A Common et al. Br J Dermatol.
13Natural and Sun-Induced Aging of Human Skin by Laure Rittié and Gary J. Fisher. Cold Spring Harb Perspect Med.
14In vivo studies of the evolution of physical properties of the human skin with age by J L Leveque et al. Int J Dermatol.
16Chronic Skin Fragility of Aging by Joseph M. Dyer, DO and Richard A. Miller, DO. J Clin Aesthet Dermatol.
17Pregnancy and Skin by Rita V. Vora et al. J Family Med Prim Care.
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19Safety of skin care products during pregnancy by Pina Bozzo et al. Can Fam Physician.
20The influence of hormones on melanogenesis by P F Hall. Australas J Dermatol.
21Brain-Skin Connection: Stress, Inflammation and Skin Aging by Ying Chen and John Lyga.
22Diabetes: 12 Warning Signs That Appear On Your Skin by the American Academy of Dermatology Association.
23Skin and Nail Changes during Cancer Treatment by the National Cancer Institute.
24Got HBV? What is Your Skin Trying to Tell You? by the Hepatitis B Foundation.
25Skin pH: from basic science to basic skin care by Saba M Ali and Gil Yosipovitch. Acta Derm Venereol.
26The Relation of pH and Skin Cleansing by Jürgen Blaak and Peter Staib. Curr Probl Dermatol.
27The pH of the skin surface and its impact on the barrier function by M-H Schmid-Wendtner and H C Korting.
28Dermatology Has a Problem With Skin Color by Roni Caryn Rabin. The New York Times.
29How dermatology is failing melanoma patients with skin of color by Bryn Nelson PhD. Cancer Cytopathology.
30Diversity in dermatology: Roadmap for improvement by Ellen N. Pritchett, MD, MPH et al. American Academy of Dermatology.
31The Protective Role of Melanin Against UV Damage in Human Skin by Michaela Brenner and Vincent J. Hearing. Photochem Photobiol.
33Ethnic differences in the structural properties of facial skin by Yoriko Sugiyama-Nakagiri et al. J Dermatol Sci.
34Pseudofolliculitis barbae; current treatment options by Adebola Ogunbiyi. Clin Cosmet Investig Dermatol.
35Rosacea in skin of color: not a rare diagnosis by Amir Al-Dabagh et al. Dermatol Online J.
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38Why This On-Trend Ingredient Could Spell Bad News For Dark Skin Tones by Viola Levy. Refinery 29.
40
Topical management of striae distensae (stretch marks): prevention and therapy of striae rubrae and albae by S. Ud‐Din et al. J Eur Acad Dermatol Venereol.
41Stretch Marks by Amanda M. Oakley and Bhupendra C. Patel. StatPearls.
42Striae distensae in darker skin types: the influence of melanocyte mechanobiology by C Piérard-Franchimont et al. J Cosmet Dermatol.
44A Review of Acne in Ethnic Skin by Erica C. Davis, MD and Valerie D. Callender, MD. J Clin Aesthet Dermatol.
45,54Environmental Stressors on Skin Aging. Mechanistic Insights by Concepcion Parradoe et al. Front Pharmacol.
46,49Air pollution and skin disorders by Wendy Roberts MD, FAAD. International Journal of Women's Dermatology.
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48Airborne particle exposure and extrinsic skin aging by Andrea Vierkötter et al. J Invest Dermatol.
50The effect of environmental humidity and temperature on skin barrier function and dermatitis by K.A. Engebretsen et al. Journal of the European Academy of Dermatology & Venereology.
51Risk factors in heating, ventilating, and air-conditioning systems for occupant symptoms in US office buildings: the US EPA BASE study by M J Mendell et al. Indoor Air.
52Sun and Skin by the National Institutes of Health.
53Effect of the sun on visible clinical signs of aging in Caucasian skin by Frederic Flament. Clin Cosmet Investig Dermatol.
55When it comes to skin health, does diet make a difference? by the American Academy of Dermatology Association.
56Association Between Adult Acne and Dietary Behaviors by Laetitia Penso et al. JAMA Dermatol.
57Discovering the link between nutrition and skin aging by Silke K. Schagen et al. Dermatoendocrinol.
58Diet and psoriasis: experimental data and clinical evidence by M Wolters. Br J Dermatol.
59Regulation of exercise blood flow: Role of free radicals by Joel D Trinity et al. Free Radic Biol Med.
60Exercise for Stress and Anxiety by the Anxiety & Depression Association of America.
61Is Your Workout Causing Your Acne? by the American Academy of Dermatology Association.
62Perceived Age and Life Style. The Specific Contributions of Seven Factors Involved in Health and Beauty by Victor Gabriel et al. Maedica (Bucur).
63Cigarette smoking and lung cancer – relative risk estimates for the major histological types from a pooled analysis of case-control studies by Beate Pesch et al. Int J Cancer.
64Cigarette smoking: risk factor for premature facial wrinkling by D P Kadunce et al. Ann Intern Med.
65Does cigarette smoking make you ugly and old? by D Grady and V Ernster. Am J Epidemiol.
66Quit smoking by J. Taylor Hays, M.D. Mayo Clinic.
67Impact of Smoking and Alcohol Use on Facial Aging in Women: Results of a Large Multinational, Multiracial, Cross-sectional Survey by Greg D. Goodman, MD et al. J Clin Aesthet Dermatol.
68A Beginner's Guide to Double Cleansing and Its Importance to Your Skin-Care Routine by Macaela Mackenzie. Allure.
69Rebuild Your Ravaged Skin Barrier With This Simple 3-Step Formula by Rachel Lapidos. Well + Good.
70Are You Overwashing Your Face? by Bee Shapiro. The New York Times.
71,74Beauty sleep: experimental study on the perceived health and attractiveness of sleep deprived people by John Axelsson et al. BMJ.
72Does poor sleep quality affect skin ageing? by P Oyetakin-White. Clin Exp Dermatol.
73Acne Severity and Sleep Quality in Adults by Kory P Schrom et al. Clocks Sleep.

Additional Reading:
Dr. Lani's No-Nonsense SUN Health Guide: The Truth about Vitamin D, Sunscreen, Sensible Sun Exposure and Skin Cancer by Dr. Lani Simpson.
Sun Proof: A Practical Guide for Sun-Damaged Skin. How-To Maximize Prevention and Repair the Damage by Dr. Austin Cope.
Sun Protection For Life: Your Guide To A Lifetime Of Healthy & Beautiful Skin by Albert Rosenthal.

Contributing Experts

Dr. Erica Stevens, MD

Board-Certified Dermatologist

Dr. Erica Stevens, MD is a board-certified dermatologist at Westlake Dermatology in Austin, Texas.

Dr. William Kwan, MD

Board-Certified Dermatologist

Dr. William Kwan is a board-certified dermatologist and the founder of Kwan Dermatology in San Francisco, CA. He practices both medical and cosmetic dermatology, and is an expert in the treatment of skin of color.

Dr. Hope Mitchell, MD

Board-Certified Dermatologist

Hope Mitchell is a board certified dermatologist, a fellow of the American Academy of Dermatology, and a member of the Skin of Color Society. She is the CEO and founder of Mitchell Dermatology, which has two locations in Northwest Ohio.

Dr. Tiffany J. Libby, MD

Board-Certified Dermatologist

Dr. Libby is the Director of Mohs surgery at Brown University Warren Alpert Medical School in Providence, Rhode Island. She specializes in skin cancer treatment and aesthetics.

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