tag:theconversation.com,2011:/us/topics/skin-damage-38716/articlesSkin damage – The Conversation2024-02-29T13:17:23Ztag:theconversation.com,2011:article/2246592024-02-29T13:17:23Z2024-02-29T13:17:23ZSkin picking is often trivialised as a bad habit – but dermatillomania can be dangerous<figure><img src="https://images.theconversation.com/files/578675/original/file-20240228-24-6y8te7.jpg?ixlib=rb-1.1.0&rect=33%2C16%2C5573%2C3715&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-woman-squeezing-pimple-looking-on-284422616">Tom Wang/Shutterstock</a></span></figcaption></figure><p>Our skin is often covered with tiny imperfections – blemishes, moles, cuts and spots that we’re all guilty of picking at from time to time. Consider the temptation of that bulbous yellow head of a spot ready to erupt, or peeling back a scab that’s been there for days to find the newly healed skin beneath. </p>
<p>But for some, skin picking is not an occasional guilty pleasure, but an obsessive condition known as excoriation disorder. Or to give it a medical name, <a href="https://www.ocduk.org/related-disorders/skin-picking/">dermatillomania</a>.
It is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115927/">relatively common in the general population</a>. Self inflicted skin disorders, of which dermatillomania is one example, account for around <a href="https://pubmed.ncbi.nlm.nih.gov/31178108/">2% of clinical appointments</a> in dermatology. </p>
<p>Dermatillomania is more than just finding satisfaction in popping a volcanic spot. It is a disorder that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3731172/">can have serious</a> and even fatal consequences. It is characterised by consistent picking at the skin, which becomes a habit, much as nail biting or thumb sucking does. This may focus upon the different pigmented spots that are visible (such as moles or freckles), in an attempt to reduce their appearance or dig them from the skin. </p>
<p>If the patient also has an associated dermatological disorder <a href="https://eczemacompany.com/blogs/blog/managing-dementia-skin-picking-disorder">such as eczema</a>, psoriasis <a href="https://www.aocd.org/page/AcneExcoriee">or acne</a> which causes lesions to develop, this may exacerbate a heightened desire to eliminate the rash from the skin.</p>
<p>But the patient may also attack unblemished skin, either with the nails or using sharp objects as tools, like needles or tweezers to gouge and scrape at perceived imperfection. Some may also go as far to <a href="https://pubmed.ncbi.nlm.nih.gov/35350511/">bite at the skin</a> with their teeth. The skin picking may persist for long periods of the day, becoming an unconscious habit. In some cases, it may even extend into sleeping hours.</p>
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<p>The disorder creates progressive skin damage. Normally after sustaining a cut or injury, the area of tissue becomes flooded with restorative cells. This includes white blood cells and fibroblasts which fight infection and weave the ends of a wound back together. Constant picking of a wound disrupts the matrix and web that these cells work around, like builders on a set of scaffolding. This interferes with the normal healing processes, and <a href="https://www.medicalnewstoday.com/articles/picking-scabs">can result in permanent scarring</a>. To complicate matters further, wounds that stay open can also <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5337191/">introduce infection</a> into the skin and deeper tissues. </p>
<h2>Related disorders</h2>
<p>There are other related disorders that have a close association with dermatillomania. Hair and nails are both extensions of the skin, and the similarly named condition trichotillomania (often shortened to trich) is another example. </p>
<p>This is where the patient persistently plucks or pulls at their hairs. Like skin picking, patients with trich may describe intense relief or satisfaction in plucking, and may become agitated in the periods when they leave their hair alone.</p>
<p>Hair plucking isn’t limited to the scalp – the lashes, eyebrows and pubic regions may also be targeted. Some may also proceed to eat the hair – a condition called <a href="https://pubmed.ncbi.nlm.nih.gov/30099694/">tricophagia</a>. This is a subtype of the <a href="https://www.ncbi.nlm.nih.gov/books/NBK532242/">eating disorder pica</a>, where there is a craving for inorganic substances, or those with no nutritional value.</p>
<p>What causes the problem in the first place? There are many triggers for dermatillomania, which a doctor will try to establish in order to help. Often treating the condition involves exploring and addressing any obvious cues to start picking. Sometimes it may be as simple as being bored, or lack of engagement in a daily routine. In other cases, an association is found with mental health disorders, like anxiety or depression.</p>
<p>Dermatillomania shares many traits with <a href="https://pubmed.ncbi.nlm.nih.gov/33008538/">obsessive-compulsive disorder</a> (OCD), a two-fold condition. OCD patients become afflicted with persistent intrusive thoughts (obsessions) which compel them to carry out actions which help them alleviate the associated unpleasantness (compulsions). A common example is frequent hand washing to relieve the stress that comes from obsessive thoughts about coming into contact with germs via touch. Jack Nicholson won an Oscar for his portrayal of Melvin Udall in the 1997 film <a href="https://mghocd.org/as-good-as-it-gets/">As Good as It Gets</a>, a character who exhibits many of these traits.</p>
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<h2>How to manage the compulsion to pick</h2>
<p>There are several techniques that a skin picking patient can do to manage these urges themselves. Part of tackling habits is to provide a form of distraction. This might be using hand-held devices such a stress ball or fidget toy, to detract attention. Patients can also use simple strategies to making picking and plucking more difficult, such as wearing gloves or hats as barriers.</p>
<p>In more severe cases, clinical intervention may be required as treatment. <a href="https://pubmed.ncbi.nlm.nih.gov/28761349/">Medical treatment</a> for either existing skin or mental health conditions acting as a trigger may help, as may <a href="https://pubmed.ncbi.nlm.nih.gov/33654612/">cognitive-behavioural therapy</a> (CBT). This seeks to disconnect negative thoughts and behaviours which drive poor mental health, and make a more positive change.</p>
<p>It goes to show therefore that, for some people, the quest for dermatological perfection is more than skin deep. Our minds and skin share close physical and psychological bonds and while the habitual picking of dermatillomania might seek to iron out imperfections in skin, it could also be counter intuitive. And become a deeply ingrained obsession.</p><img src="https://counter.theconversation.com/content/224659/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dan Baumgardt does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Skin picking shouldn’t be dismissed as merely a bad habit. It’s a disorder that can have serious –even fatal – consequences.Dan Baumgardt, Senior Lecturer, School of Physiology, Pharmacology and Neuroscience, University of BristolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2196402024-01-08T12:09:28Z2024-01-08T12:09:28ZSunscreen: why wearing it even in winter could be a good idea<figure><img src="https://images.theconversation.com/files/567833/original/file-20240104-27-a4kzki.jpg?ixlib=rb-1.1.0&rect=11%2C0%2C3854%2C2590&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Sun's radiation can still damage our skin even in winter.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-using-sunscreen-257081962">Stanislav Nikolov/ Shutterstock</a></span></figcaption></figure><p>Sunscreen has taken centre stage in many skincare routines, especially among those hoping to prevent visible signs of ageing. But while it makes sense to wear sunscreen every day in the summer when the sun’s rays are most powerful, many may wonder whether there’s any benefit of wearing sunscreen daily in the winter months.</p>
<p>The sun’s radiation can reach us during all times of the year. This means that in both summer and winter, we are exposed to infrared radiation, as well as UVA and UVB rays.</p>
<p>UVB is mainly responsible for sunburn and DNA damage – and can also <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3709783/">cause skin cancers</a> as a result of long-term exposure. UVA radiation does contribute to these processes somewhat, but it’s less effective at doing so. UVA can penetrate deeper into the skin, however, which can damage the collagen – a key part of the skin that keeps it firm and elastic. This can cause the <a href="https://pubmed.ncbi.nlm.nih.gov/25234829/">skin to age faster</a>, leading to wrinkles, fine lines and changes in pigmentation.</p>
<p>The amount of UVA and UVB radiation that reaches the Earth’s surface changes across the seasons. This is due to the angle of the Sun in the sky, as well as other factors such as latitude and time of day.</p>
<p>For example, let’s compare how <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/php.12422">UVA and UVB radiation varies</a> at solar noon in London, UK and Kuala Lampur, Malaysia (which is near the equator).</p>
<p>In latitudes closer to the equator (such as in Kuala Lampur), the amount of UVA and UVB radiation throughout the year remains fairly consistent. But in higher latitudes, such as London, there’s almost no UVB radiation throughout the winter months – whereas there’s still some UVA radiation.</p>
<p>Not only that, but people living further from the equator may tend to spend less time exposed to the Sun in winter due to the colder temperatures and variable weather. And when they do go outside, they may cover their skin up – usually leaving only their face exposed to the Sun for much shorter periods of time.</p>
<p>But UVA radiation can still penetrate through clouds and windows. While our exposure to these rays is probably minimal, skin damage from UV exposure is <a href="https://www.sciencedirect.com/science/article/pii/S0079610706000162">accumulated over decades</a>, so anything that can be done to reduce exposure (and damage) over time may be beneficial. This is also true of UVB exposure – although it is less relevant in winter months at higher latitudes.</p>
<p>This may be where daily sunscreen use during the winter is still of benefit. Sunscreens are formulated to reduce exposure to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6978633/">both UVB and UVA rays</a> – although they are usually more effective at reducing exposure to UVB radiation. They have been designed in this way to prevent the most damaging effects of the Sun, such as sunburn and DNA damage. The impact of exposure to UVA radiation has only been considered more recently.</p>
<p>Numerous studies have shown regular sunscreen use over many years is effective at <a href="https://onlinelibrary.wiley.com/doi/10.1111/phpp.12109">preventing skin damage</a>, photoaging and skin cancers. The most robust trials suggest daily sunscreen use is most effective, but this will be dependent on the factors discussed above.</p>
<h2>The effects of altitude and snow</h2>
<p>One place where winter sunscreen use is especially important is when skiing or snowboarding – or when you’re otherwise going to be outside for extended periods of time, at higher altitudes on snow-covered mountains.</p>
<p>Both altitude and snow can increase the doses of <a href="https://www.who.int/news-room/questions-and-answers/item/radiation-ultraviolet-(uv)">UVA and UVB radiation</a> a person receives. Snow can reflect up to 80% of UV radiation emitted by the Sun – effectively almost doubling the doses received. Also, for every 1,000-foot increase in altitude, there’s a 10% increase in UV exposure. This is why it’s essential to protect the skin and eyes by wearing sunscreen, protective clothing and sunglasses that block both types of UV ray. This is also true when spending time in snowy environments, such as when hiking or skating.</p>
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<img alt="A man and a woman snowshoe through a snowy field on a sunny day." src="https://images.theconversation.com/files/567835/original/file-20240104-19-ml8ihz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/567835/original/file-20240104-19-ml8ihz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/567835/original/file-20240104-19-ml8ihz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/567835/original/file-20240104-19-ml8ihz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/567835/original/file-20240104-19-ml8ihz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/567835/original/file-20240104-19-ml8ihz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/567835/original/file-20240104-19-ml8ihz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Snow reflects UV radiation.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/snowshoe-walkers-running-powder-snow-beautiful-1279921384">Lukas Gojda/ Shutterstock</a></span>
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<p>Sunscreens are generally regarded as safe and tend to have few adverse effects, so you don’t need to worry too much about wearing one throughout the year. However, there are some points to consider, especially if you have skin conditions. For example, sunscreen can <a href="https://www.byrdie.com/does-sunscreen-cause-acne-or-help-it-7546147">exacerbate acne</a> and cause <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7759112/">irritation and allergic reactions</a> – although these are rare.</p>
<p>There are also emerging concerns from regulatory agencies about the <a href="https://jamanetwork.com/journals/jama/fullarticle/2759002">absorption of UV filters into the body</a>. However, the consequences of such absorption and the potential affects on health are not well defined and require more research.</p>
<p>Still, the benefits of sunscreen have been widely demonstrated – as has their safety. So if you want to prevent premature signs of ageing, it’s important to use sunscreen at all times you may be exposed to the Sun – especially in the summer months. While the benefits of wearing sunscreen in winter are less well defined, there’s probably no harm in wearing one if you want to.</p>
<p>If you decide to use sunscreen in winter, use ones that have broad spectrum five-star UVA protection. For day-to-day use, high SPF sunscreens are unlikely to provide a large benefit, particularly if spending only short periods outside. However, if skiing, a <a href="https://www.jaad.org/article/S0190-9622(17)31086-1/fulltext">high-SPF sunscreen</a> with five-star UVA protection would be beneficial.</p><img src="https://counter.theconversation.com/content/219640/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karl Lawrence has previously received funding from the sunscreen industry and hold patents related to sunscreen ingredients.</span></em></p>Regular sunscreen use over many years is shown to be effective at preventing skin damage, photoaging and skin cancers.Karl Lawrence, Research fellow, King's College LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2093712023-08-11T12:38:49Z2023-08-11T12:38:49ZSkin cancer screening guidelines can seem confusing – three skin cancer researchers explain when to consider getting checked<figure><img src="https://images.theconversation.com/files/539388/original/file-20230725-17-v7y631.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C5454%2C3714&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A history of sunburns may put people at greater risk of developing skin cancer.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/young-womans-back-being-examined-at-a-royalty-free-image/166130792?phrase=skin+cancer+screening&adppopup=true">dnberty/iStock via Getty Images Plus</a></span></figcaption></figure><p><em>Protecting oneself from the summer sun and its damaging ultraviolet rays is often not straightforward. And public health messaging around when and how to be screened for skin cancer has become somewhat confusing.</em></p>
<p><em>In April 2023, the U.S. Preventive Services Task Force, an independent national panel of science experts, provided <a href="https://doi.org/10.1001/jama.2023.4342">updated recommendations on skin cancer</a> screening following a <a href="https://doi.org/10.1001/jama.2023.3262">systematic review of existing research</a>. The task force concluded that the evidence does not support annual widespread skin screening of adolescents and adults, but that catching cancers at the earliest stages reduces the risk of death from skin cancer.</em> </p>
<p><em>At first glance, these statements appear conflicting. So The Conversation asked dermatology experts <a href="https://som.cuanschutz.edu/Profiles/Faculty/Profile/7842">Enrique Torchia</a>, <a href="https://som.cuanschutz.edu/Profiles/Faculty/Profile/20820">Tamara Terzian</a> and <a href="https://coloradosph.cuanschutz.edu/resources/directory/directory-profile/Box-Neil-UCD4553">Neil Box</a> to help unravel the task force recommendations, what they mean for the public and how people can minimize their skin cancer risk.</em></p>
<h2>How common is skin cancer in the US?</h2>
<p>Skin cancer affects about 6 million Americans yearly, according to the Centers for Disease Control and Prevention. This number is <a href="https://www.cancer.org/research/cancer-facts-statistics/all-cancer-facts-figures/2023-cancer-facts-figures.html">more than all other types of cancers combined</a>. </p>
<p><a href="https://medschool.cuanschutz.edu/colorado-cancer-center/for-patients-families/cancers-we-treat/skin-cancer">Basal cell carcinoma and squamous cell carcinoma</a> – collectively known as keratinocyte cancers – account for more than <a href="https://doi.org/10.1016/j.jaad.2021.03.109">97% of skin cancer cases</a>, but invasive melanomas cause the most deaths. Keratinocyte cancers arise from basal cells and the more differentiated squamous cells in the epidermis – the top layer of skin – whereas melanoma comes from melanocytes found at the junction of the epidermis and the dermis, or middle layer. </p>
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<a href="https://images.theconversation.com/files/542208/original/file-20230810-21547-6nm4f8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram showing human skin layers." src="https://images.theconversation.com/files/542208/original/file-20230810-21547-6nm4f8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/542208/original/file-20230810-21547-6nm4f8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542208/original/file-20230810-21547-6nm4f8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542208/original/file-20230810-21547-6nm4f8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542208/original/file-20230810-21547-6nm4f8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542208/original/file-20230810-21547-6nm4f8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542208/original/file-20230810-21547-6nm4f8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The majority of skin cancers arise from cells within the epidermis, or top layer, of the skin.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/human-skin-layers-royalty-free-illustration/1149397551?phrase=dermis+layers&adppopup=true">About time/ iStock via Getty Images Plus</a></span>
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<p>Unlike normal cells, skin cancer cells grow without constraints, acquiring the ability to invade down into the dermis.</p>
<p>Invasive melanomas are classified by stages 1 through 4. The higher the number, the more invasive the tumor is into the dermis and to other organs of the body in <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/metastasis">a process called metastasis</a>. </p>
<h2>What are the main causes of skin cancer?</h2>
<p>Overexposure to ultraviolet rays causes the majority of skin cancers. Both light- and dark-skinned people <a href="https://www.aad.org/media/stats-skin-cancer">can get skin cancer</a>, but light-skinned individuals have a greater risk. Those with light skin, light or red hair, or with numerous moles, are more susceptible to skin damage and severe burns by ultraviolet rays. Darker-skinned individuals produce more of the <a href="https://my.clevelandclinic.org/health/body/22615-melanin">protective pigment called melanin</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/542237/original/file-20230810-23008-qfmzoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Cartoon of a young female on the left before sunburn and on the right with a sunburned face, with sunrays hitting an illustration of the skin layers in the middle." src="https://images.theconversation.com/files/542237/original/file-20230810-23008-qfmzoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/542237/original/file-20230810-23008-qfmzoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/542237/original/file-20230810-23008-qfmzoe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/542237/original/file-20230810-23008-qfmzoe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/542237/original/file-20230810-23008-qfmzoe.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/542237/original/file-20230810-23008-qfmzoe.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/542237/original/file-20230810-23008-qfmzoe.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Overexposure to UV light damages skin, causing sunburns and stimulating melanocytes to make melanin, the protective pigment that darkens skin during tanning. Sunscreen can protect skin from UV damage.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/care-before-after-image-royalty-free-illustration/609443652">chombosan/iStock via Getty Images Plus</a></span>
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<p>Tanning serves as the body’s protective response to skin damage from ultraviolet rays, stimulating melanocytes to <a href="https://doi.org/10.1111/exd.14260">produce melanin</a>. People who use tanning beds are at a higher risk of skin damage and skin cancers. This is why the American Academy of Dermatology and others <a href="https://www.aad.org/media/stats-indoor-tanning">recommend avoiding tanning beds</a>. Outdoor workers or those who spend time outdoors recreationally, especially at higher elevation, are exposed to more ultraviolet light. </p>
<p>A history of sunburns also puts people at greater risk of developing skin cancer. Because the damage from ultraviolet, or UV, exposure is cumulative, skin cancer is <a href="https://www.skincancer.org/skin-cancer-information/skin-cancer-facts/">more prevalent in people over 55 years old</a>. </p>
<p>Survivors of skin cancers are also <a href="https://doi.org/10.1111/jdv.12887">more likely to get another cancer</a> in their lifetime. Moreover, those who had a squamous cell carcinoma may be at <a href="https://doi.org/10.1007/s00403-017-1724-5">higher risk of dying from noncancer causes</a>. The reasons for these observations are not well understood but may be linked to inflammation or altered immunity, or both, in skin cancer survivors.</p>
<h2>What is the debate behind screening?</h2>
<p>The ongoing debate revolves around whether more screening reduces the death toll from melanoma. </p>
<p>Since the early 1990s, the incidence of melanoma has risen dramatically in the U.S. This increase may be due in part to more emphasis on early detection. <a href="https://doi.org/10.1056/NEJMsb2019760">More melanomas have been found</a>, particularly those identified at the earliest stage, also known as <a href="https://www.aimatmelanoma.org/stages-of-melanoma/">stage 0</a> or melanoma <em>in situ</em>. </p>
<p>Despite this, the rate of death per capita from melanoma has remained unchanged over the last 40 years. Researchers have <a href="https://doi.org/10.1056/NEJMsb2019760">attributed this fact to overdiagnosis</a>, in which suspicious lesions are diagnosed as early melanomas, even though they may not actually be melanomas or progress to be invasive melanomas, which have <a href="https://www.cancer.org/cancer/types/melanoma-skin-cancer/detection-diagnosis-staging/survival-rates-for-melanoma-skin-cancer-by-stage.html">the worst prognosis</a>. </p>
<p>This observation suggests that widespread screening may result in unnecessary surgical biopsies and increased psychological stress associated with a cancer diagnosis. </p>
<p>However, a recent study published after the task force recommendations showed that patients with melanoma <em>in situ</em> had a slight risk of death from melanoma, but <a href="https://doi.org/10.1001/jamadermatol.2023.1494">lived longer than the average person</a>. The authors speculated that the diagnosis of early stage melanoma resulted in a greater awareness of the patient’s overall health, leading to more health-conscious behavior. So, there may be additional benefits to screening the public. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/UnCUcFJJDSA?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Regular self-exams help you catch skin cancer early, when it’s most treatable.</span></figcaption>
</figure>
<h2>What did the task force base its new recommendations on?</h2>
<p>The task force reviewed current and past data on the major types of skin cancers. The expert panel relied in part on the results of a large public <a href="https://doi.org/10.1016/j.jaad.2010.11.016">skin cancer screening program</a> in Germany. This program initially examined 20-year-olds from a single state and subsequently <a href="http://dx.doi.org/10.1136/bmjopen-2015-008158">expanded the program nationwide</a> to include people over 35. However, death rates from melanoma were unchanged compared to areas where skin exams were not offered. </p>
<p>The results of the German screening program did not provide strong confidence that annual widespread public screening of adults would reduce skin cancer deaths compared with current practices. However, the task force did conclude, based on numerous studies involving millions of patients, that detecting melanoma at early stages when tumors are less invasive <a href="https://doi.org/10.1001/jama.2023.3262">improved patient survival</a>. </p>
<h2>When should you get a skin exam?</h2>
<p>The American Academy of Dermatology, the <a href="https://www.skincancer.org/early-detection/self-exams/">Skin Cancer Foundation</a> and the <a href="https://www.cdc.gov/cancer/skin/basic_info/screening.htm">CDC recommend</a> <a href="https://www.aad.org/news/aad-statement-uspstf-cancer-screeening">monthly self-checks</a>. This requires familiarity with your skin or that of your family members. Luckily, there are many online guides on detecting suspicious skin lesions. </p>
<p>Whenever you have a concern about a spot on your skin, seek medical advice. Annual or more frequent exams are also <a href="https://www.aad.org/dw/dw-insights-and-inquiries/2019-archive/november/dwii-11-13-19-the-naked-truth-about-total-body-skin-examination-a-lesson-from-goldilocks-and-the-three-bears">recommended for high-risk groups</a>. This includes those who are older or susceptible to getting skin cancers, skin cancer survivors and immunocompromised people like organ transplant recipients. </p>
<p>Between 8% to 30% of the U.S. population <a href="https://doi.org/10.1016/j.jaad.2008.03.013">gets an annual skin exam</a>, but the numbers are imprecise because screening rates have not been well studied. Access to screening may also be challenging for some people. In response, nonprofits like the <a href="https://www.aad.org/public/public-health/skin-cancer-screenings/find-a-screening">American Academy of Dermatology</a>, <a href="https://www.skincancer.org/early-detection/destination-healthy-skin/">the Skin Cancer Foundation</a> and <a href="https://www.thesunbus.org/">The Sun Bus</a> provide resources for free exams. However, these opportunities are often few and far between. </p>
<p>Based on internal unpublished data from The Sun Bus, our mobile clinic operating in the central and southern U.S., a significant number of individuals seeking free exams were primarily motivated by concerns about a skin lesion and the cost of visiting a dermatologist.</p>
<p><iframe id="X7MiE" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/X7MiE/8/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>Our data suggests that screening programs attract individuals who are proactive and health-conscious.</p>
<h2>How can you minimize the risk of skin cancer?</h2>
<p>Strategies that limit UV exposure will <a href="https://www.cdc.gov/cancer/skin/basic_info/sun-safety.htm">reduce skin cancer risk</a>. This includes avoiding sunburns by: </p>
<ul>
<li>Finding shade</li>
<li>Covering exposed skin</li>
<li>Using a hat and sunglasses</li>
<li>Using and reapplying sunscreen routinely</li>
</ul>
<p>A broad-spectrum sunscreen and lip balm with a Sun Protection Factor (SPF) of at least 30 when applied correctly will <a href="https://www.aad.org/public/everyday-care/sun-protection/shade-clothing-sunscreen/how-to-select-sunscreen">block 97% of ultraviolet rays</a>. Apply these products 15-20 minutes before heading out into the sun and reapply every two hours. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/L7dH-I2qLU8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Don’t wait until you’re in the sun to apply sunscreen.</span></figcaption>
</figure>
<p>UV light is most intense between the hours of 10 a.m. to 4 p.m. It is a good idea to pay attention to the UV index – a forecast by zip code that <a href="https://www.epa.gov/sunsafety/uv-index-1">projects risk of UV exposure</a> on a scale of 0 to 11. A UV index below 2 is the safest, whereas 11 represents extreme danger. </p>
<p>Ideally, clothing should be rated with an Ultraviolet Protection Factor (UPF) of 50. Wearing regular long-sleeved clothing and pants will also <a href="https://www.skincancer.org/skin-cancer-prevention/sun-protection/sun-protective-clothing/">provide some protection</a>. </p>
<p>These measures can keep your skin healthy into your golden years by reducing skin aging and cancer caused by ultraviolet light.</p><img src="https://counter.theconversation.com/content/209371/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Enrique Torchia received funding from American Cancer Society and Dermatology Foundation. </span></em></p><p class="fine-print"><em><span>Neil Box receives funding from the National Institutes of Health and the American Skin Association. He is affiliated with Caris Life Sciences and the Colorado Melanoma Foundation. </span></em></p><p class="fine-print"><em><span>Tamara Terzian received funding from National Institutes of Health, Dermatology Foundation, Skin Cancer Foundation, American Skin Association, American Cancer Society, Cancer League of Colorado, and Colorado Clinical Translational Sciences Institute. She is affiliated with the Colorado Melanoma Foundation and the University of Colorado. </span></em></p>Widespread screening for skin cancer may not be necessary, but it is important to understand the risks behind UV overexposure and to get checked early if you have concerns.Enrique Torchia, Assistant Research Professor of Dermatology, University of Colorado Anschutz Medical CampusNeil Box, Associate Clinical Professor of Dermatology and Epidemiology, University of Colorado Anschutz Medical CampusTamara Terzian, Assistant Professor of Dermatology, University of Colorado Anschutz Medical CampusLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2083632023-07-12T02:17:21Z2023-07-12T02:17:21ZWhy is eczema sometimes treated with a diluted bleach bath? And what do I need to know before trying it?<figure><img src="https://images.theconversation.com/files/533621/original/file-20230623-15-xi7q7.jpg?ixlib=rb-1.1.0&rect=8%2C33%2C5621%2C3722&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Diluted bleach baths are a common treatment doctors and nurses use for patients with more severe eczema. It is important to note they may not replace other treatments and may not be suitable for everyone. </p>
<p>This treatment should only ever be used under the guidance of a dermatologist or doctor, who can advise if it’s appropriate and tailor the dilution ratio to suit the individual’s condition.</p>
<p>So why and how does it work for some eczema sufferers? And what should one know before trying it?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ive-always-wondered-why-do-we-get-dark-circles-under-our-eyes-90172">I've always wondered: why do we get dark circles under our eyes?</a>
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</em>
</p>
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<h2>Germs can colonise damaged eczema skin</h2>
<p>Eczema is a genetic condition that causes a person’s skin to be easily inflamed by certain triggers, such as hot water or soaps. The person’s skin barrier becomes damaged and itchy, allowing germs to get established and cause even more problems.</p>
<p>The most common germ found in the damaged eczema skin is <em>staphylococcus aureus</em>. Certain toxic materials known as “membrane-bound vesicles” are released by the staph germ, which causes an even more profound reaction in the skin, <a href="https://pubmed.ncbi.nlm.nih.gov/27910159/">worsening the eczema</a>. Treating – or at least reducing – the amount of staph in the skin can help the eczema recover.</p>
<p>When eczema is very active, the skin literally bubbles with fluid and can begin to weep. Bacteria love to colonise and infect this type of eczema. This process is known as “impetiginisation”. </p>
<p>When this process occurs without eczema, it is called impetigo (also known as school sores). </p>
<p>A solution of water and sodium hypochlorite (in other words, bleach) will rapidly <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1580803/pdf/amjphnation01146-0053.pdf">kill</a> germs. And we know from <a href="https://pubmed.ncbi.nlm.nih.gov/17015593/">studies</a> on wounds that simple washing of a wound reduces the number of bacteria. </p>
<p>So it’s likely a gentle washing action is part of the effect, in some cases, and could be made more effective with subtle water jets.</p>
<p>For example, using a water squeeze toy for young children to create a gentle wash of water could help remove some of the build-up of body fluids in the broken eczema areas. </p>
<p>This would obviously need to be done very gently so it was not uncomfortable. Friction and rubbing of eczema – particularly with cloths and towels – generally makes things much worse.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/535989/original/file-20230706-1723-hte9mu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/535989/original/file-20230706-1723-hte9mu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/535989/original/file-20230706-1723-hte9mu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/535989/original/file-20230706-1723-hte9mu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/535989/original/file-20230706-1723-hte9mu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/535989/original/file-20230706-1723-hte9mu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/535989/original/file-20230706-1723-hte9mu.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/535989/original/file-20230706-1723-hte9mu.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Friction and rubbing can make eczema worse.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Reducing inflammation</h2>
<p>Researchers have also shown sodium hypochlorite can <a href="https://doi.org/10.1172/JCI70895">reduce inflammation</a> in the skin. This is another reason the treatment is recommended.</p>
<p>Eczema often involves a vicious cycle of inflammation, where redness and increasing itchiness leads to scratching and even more irritation. The skin breaks even more and the eczema worsens, leading to yet more inflammation. </p>
<p>A diluted bleach bath can help break this vicious cycle.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/535995/original/file-20230706-27-g7af4c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/535995/original/file-20230706-27-g7af4c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/535995/original/file-20230706-27-g7af4c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/535995/original/file-20230706-27-g7af4c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/535995/original/file-20230706-27-g7af4c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/535995/original/file-20230706-27-g7af4c.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/535995/original/file-20230706-27-g7af4c.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/535995/original/file-20230706-27-g7af4c.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The bleach should be diluted in the bathwater to ensure it is safe for your skin.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>You need to know what you’re doing</h2>
<p>Diluted bleach bath instructions need to be tailored to the eczema, so don’t try it at home unless you’ve been advised by a dermatologist or doctor. An example of how to perform a bleach bath might look like this:</p>
<p><strong>1. Dilution ratio:</strong> The bleach should be diluted in the bathwater to ensure it is safe for your skin. A typical dilution ratio may be ½ cup (120 ml) of household bleach (containing 5-6% sodium hypochlorite) per 150 litres of lukewarm water. However, the exact dilution ratio may vary based on the severity of your eczema, age and other factors. Children may need less bleach in their bath. Check with your doctor because getting the ratio wrong can cause pain and harm.</p>
<p><strong>2. Soak time:</strong> The recommended soak time in the bleach bath is usually around ten minutes. During this time, gently pat or submerge your affected skin areas in the water. Avoid scrubbing or rubbing the skin vigorously, as it may further irritate or damage the skin.</p>
<p><strong>3. Rinse thoroughly:</strong> After the designated soak time, carefully rinse off the bleach solution from your body with cool water. Make sure to remove all traces of the bleach, as residual bleach left on the skin may cause irritation.</p>
<p><strong>4. Moisturise:</strong> After the bath, promptly apply a moisturiser or emollient to your skin while it is still slightly damp. This helps lock in moisture and maintain hydration, which is crucial for eczema management.</p>
<p><strong>5. Frequency:</strong> The frequency of bleach baths can vary depending on your specific condition. Typically, they are done two to three times a week, but this may vary.</p>
<p><strong>6. Monitoring and follow-up:</strong> It is essential to monitor your skin’s response to bleach baths. If you notice any increased redness, irritation or discomfort, discontinue the baths and talk to your dermatologist.</p>
<hr>
<p>
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<strong>
Read more:
<a href="https://theconversation.com/how-to-treat-scars-at-home-and-hopefully-make-them-disappear-193948">How to treat scars at home – and hopefully make them disappear</a>
</strong>
</em>
</p>
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<img src="https://counter.theconversation.com/content/208363/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Freeman does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>When eczema is very active, the skin literally bubbles with fluid and can begin to weep. Bacteria love to colonise and infect this type of eczema.Michael Freeman, Associate Professor of Dermatology, Bond UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1875592022-09-06T12:37:31Z2022-09-06T12:37:31ZHuman skin stood up better to the sun before there were sunscreens and parasols – an anthropologist explains why<figure><img src="https://images.theconversation.com/files/480836/original/file-20220824-4026-m7s9pf.jpg?ixlib=rb-1.1.0&rect=663%2C34%2C5087%2C3794&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The sun’s rays often feel good on your skin, but can cause serious damage.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/close-up-of-woman-against-sky-during-sunset-royalty-free-image/1340270649">Maksim Chernyshev/EyeEm via Getty Images</a></span></figcaption></figure><p>Human beings have a conflicted relationship with the sun. People love sunshine, but then get hot. Sweat gets in your eyes. Then there are all the protective rituals: the sunscreen, the hats, the sunglasses. If you stay out too long or haven’t taken sufficient precautions, your skin lets us you know with an angry sunburn. First the heat, then the pain, then the remorse.</p>
<p>Were people always this obsessed with what the sun would do to their bodies? <a href="https://scholar.google.com/citations?user=NIAvKr8AAAAJ&hl=en&oi=ao">As a biological anthropologist</a> who has studied primates’ adaptations to the environment, I can tell you the short answer is “no,” and they didn’t need to be. For eons, skin stood up to the sun.</p>
<h2>Skin, between you and the world</h2>
<p>Human beings evolved under the sun. Sunlight was a constant in people’s lives, warming and guiding them through the days and seasons. <em>Homo sapiens</em> spent the bulk of our prehistory and history outside, mostly naked. Skin was the primary interface between our ancestors’ bodies and the world.</p>
<p>Human skin was adapted to whatever conditions it found itself in. People took shelter, when they could find it, in caves and rock shelters, and got pretty good at making portable shelters from wood, animal skins and other gathered materials. At night, they huddled together and probably covered themselves with fur “blankets.” But during the active daylight hours, people were outdoors and their mostly bare skin was what they had.</p>
<p>During a person’s lifetime, <a href="https://medlineplus.gov/ency/anatomyvideos/000125.htm">skin responds to routine exposure to the sun</a> in many ways. The surface layer of the skin – the epidermis – <a href="https://newsinhealth.nih.gov/2014/07/sun-skin">becomes thicker by adding more layers of cells</a>. For most people, the skin becomes gradually darker as specialized cells kick into action to produce a <a href="https://my.clevelandclinic.org/health/body/22615-melanin">protective pigment called eumelanin</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/480838/original/file-20220824-12-e8zgi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="cross-sectional diagram of skin's layers with sunlight hitting the surface and showing increased production of melanin" src="https://images.theconversation.com/files/480838/original/file-20220824-12-e8zgi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480838/original/file-20220824-12-e8zgi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480838/original/file-20220824-12-e8zgi6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480838/original/file-20220824-12-e8zgi6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480838/original/file-20220824-12-e8zgi6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480838/original/file-20220824-12-e8zgi6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480838/original/file-20220824-12-e8zgi6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Exposure to the sun’s rays triggers production of more protective eumelanin, which also darkens the skin’s appearance.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/tanning-process-skin-human-anatomy-royalty-free-illustration/645165034">ttsz/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>This remarkable molecule absorbs most visible light, causing it to look very dark brown, almost black. Eumelanin also absorbs damaging ultraviolet radiation. Depending on their genetics, people produce different amounts of eumelanin. Some have a lot and are able to produce a lot more when their skin is exposed to sun; others have less to start out with and produce less when their skin is exposed.</p>
<p><a href="https://scholar.google.com/citations?user=NIAvKr8AAAAJ&hl=en&oi=ao">My research on</a> <a href="https://doi.org/10.1111/pcmr.12976">the evolution of human skin pigmentation</a> has shown that the skin color of people in prehistory was tuned to local environmental conditions, primarily to local levels of ultraviolet light. People who lived under strong UV light – like you’d find near the equator – year in and year out had darkly pigmented and highly tannable skin capable of making a lot of eumelanin. People who lived under weaker and more seasonal UV levels – like you’d find in much of northern Europe and northern Asia – had lighter skin that had only limited abilities to produce protective pigment.</p>
<p>With only their feet to carry them, our distant ancestors didn’t move around much during their lives. Their skin adapted to subtle, seasonal changes in sunlight and UV conditions by producing more eumelanin and becoming darker in the summer and then losing some pigment in the fall and winter when the sun wasn’t so strong. Even for people with lightly pigmented skin, painful sunburns would have been exceedingly rare because there was never a sudden shock of strong sun exposure. Rather, as the sun strengthened during spring, the top layer of their skin would have gotten <a href="https://doi.org/10.1007/978-3-540-89656-2_60">gradually thicker over weeks and months of sun exposure</a>.</p>
<p>This is not to say that the skin would have been undamaged by today’s standards: Dermatologists would be appalled by the leathery and wrinkled appearance of the sun-exposed skin of our ancestors. Skin color, like the levels of sun itself, changed with the seasons and skin quickly showed its age. This is still the case for people who live traditional, mostly outdoor, lives in many parts of the world.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/479980/original/file-20220818-27-79ac87.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a squatting old man with weathered skin" src="https://images.theconversation.com/files/479980/original/file-20220818-27-79ac87.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/479980/original/file-20220818-27-79ac87.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/479980/original/file-20220818-27-79ac87.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/479980/original/file-20220818-27-79ac87.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/479980/original/file-20220818-27-79ac87.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/479980/original/file-20220818-27-79ac87.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/479980/original/file-20220818-27-79ac87.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Chronic unprotected sun exposure can damage skin, with effects that look like those on this farmer in India.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:2020_Indian_farmers%27_protest_-_old_man_sitting.jpg">Randeep Maddoke/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>There is no preserved skin from thousands of years ago for scientists to study, but we can infer from the effects of sun exposure on modern people that the damage was similar. <a href="https://doi.org/10.1111/j.1365-2133.2009.09565.x">Chronic sun exposure</a> <a href="https://doi.org/10.1016/S1011-1344(01)00198-1">can lead to skin cancer</a>, but rarely of the variety – <a href="https://doi.org/10.1016/j.bjps.2006.05.008">melanoma</a> – that would cause death during reproductive age.</p>
<h2>Indoor living changed skin</h2>
<p>Until around 10,000 years ago – a drop in the bucket of evolutionary history – human beings made their living by <a href="https://www.history.com/topics/pre-history/hunter-gatherers">gathering foods, hunting and fishing</a>. Humanity’s relationship with the sun and sunlight changed a lot after people started to settle down and live in permanent settlements. <a href="https://www.smithsonianmag.com/history/the-seeds-of-civilization-78015429/">Farming and food storage</a> were associated with the development of immovable buildings. By around 6000 B.C. many people throughout the world were spending more time in walled settlements, and more time indoors.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/480840/original/file-20220824-4729-j9lpxl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="line drawing of royal bearded man followed by two smaller men with parasol and fly whisk" src="https://images.theconversation.com/files/480840/original/file-20220824-4729-j9lpxl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/480840/original/file-20220824-4729-j9lpxl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1019&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480840/original/file-20220824-4729-j9lpxl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1019&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480840/original/file-20220824-4729-j9lpxl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1019&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480840/original/file-20220824-4729-j9lpxl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1281&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480840/original/file-20220824-4729-j9lpxl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1281&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480840/original/file-20220824-4729-j9lpxl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1281&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Persian King Darius the Great, who lived more than 2,500 years ago, is portrayed being shielded from the sun.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/king-darius-the-great-followed-by-his-royalty-free-illustration/1367186124">Luisa Vallon Fumi/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>While most people still spent most of their time outside, some stayed indoors if they could. Many of them <a href="https://www.folkwear.com/blogs/news/historyoftheparasol">started protecting themselves from the sun</a> when they did go out. By at least 3000 B.C., a whole industry of sun protection grew up to create gear of all sorts – parasols, umbrellas, hats, tents and clothing – that would protect people from the discomfort and inevitable darkening of the skin associated with lengthy sun exposure. While some of these were originally reserved for nobility – like the parasols and umbrellas of ancient Egypt and China – these luxury items <a href="https://doi.org/10.1007/s11199-017-0785-4">began to be made</a> and <a href="https://doi.org/10.1080/17532523.2016.1281875">used more widely</a>.</p>
<p>In some places, people even developed <a href="https://doi.org/10.1371/journal.pone.0136090">protective pastes made out of minerals</a> and plant residues – <a href="https://doi.org/10.1111/jocd.14004">early versions of modern sunscreens</a> – to protect their exposed skin. Some, like the <a href="https://www.scmp.com/lifestyle/fashion-beauty/article/3100999/all-natural-sunscreen-and-beauty-product-thanaka-paste-has">thanaka paste used by people in Myanmar</a>, still persists today.</p>
<p>An important consequence of these practices in traditional agricultural societies was that people who spent most of their time indoors considered themselves privileged, and their lighter skin announced their status. A “farmer’s tan” was not glamorous: <a href="https://www.ucpress.edu/book/9780520283862/living-color">Sun-darkened skin was a penalty associated with hard outdoor work</a>, not the <a href="https://doi.org/10.2105/AJPH.2008.144352">badge of a leisurely vacation</a>. From Great Britain to China, Japan and India, suntanned skin became associated with a life of toil.</p>
<p>As people have moved around more and faster over longer distances in recent centuries, and spend more time indoors, their skin hasn’t caught up with their locations and lifestyles. Your levels of eumelanin probably aren’t perfectly adapted to the sun conditions where you live and so aren’t able to protect you the same way they might have your ancient ancestors.</p>
<p>Even if you’re naturally darkly pigmented or capable of tanning, everyone is susceptible to <a href="https://doi.org/10.1001/jamadermatol.2017.4201">damage caused by episodes of sun exposure</a>, especially after long breaks spent completely out of the sun. The “vacation effect” of sudden strong UV exposure is really bad because a sunburn signals damage to the skin that is never completely repaired. It’s like a bad debt that presents itself as prematurely aged or precancerous skin many years later. There is no healthy tan – a tan doesn’t protect you from further sun damage, it’s the sign of damage itself.</p>
<p>People may love the sun, but we’re not our ancestors. Humanity’s relationship with the sun has changed, and this means changing your behavior to save your skin.</p><img src="https://counter.theconversation.com/content/187559/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nina G. Jablonski consults for L'Oreal and has received funding from the National Science Foundation, The Leakey Foundation, The Wenner-Gren Foundation, The Robert Wood Johnson Foundation, and The Rockefeller Foundation.</span></em></p>Our ancient ancestors didn’t have clothes or houses – but that constant exposure to the sun helped their skin protect itself from the worst sun damage.Nina G. Jablonski, Evan Pugh University Professor of Anthropology, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1341462020-04-13T19:48:13Z2020-04-13T19:48:13ZMy skin’s dry with all this hand washing. What can I do?<figure><img src="https://images.theconversation.com/files/324520/original/file-20200401-66125-znylpp.jpg?ixlib=rb-1.1.0&rect=0%2C8%2C1920%2C1270&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/E6fONgWV1Uo">Irina Ba/Unsplash</a></span></figcaption></figure><p>Washing your hands is one of the <a href="https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public">crucial ways</a> <a href="https://www.health.gov.au/news/health-alerts/novel-coronavirus-2019-ncov-health-alert/what-you-need-to-know-about-coronavirus-covid-19#good-hygiene">we can all help</a> limit the spread of COVID-19.</p>
<p>Regularly and thoroughly washing your hands with soap and water for at least 20 seconds, or using an alcohol-based hand sanitiser, are key steps to reducing the risk.</p>
<p>But with all this hand washing, it’s easy to get dry skin or for existing skin conditions to flare up.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/yes-washing-our-hands-really-can-help-curb-the-spread-of-coronavirus-132915">Yes, washing our hands really can help curb the spread of coronavirus</a>
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</em>
</p>
<hr>
<h2>What’s happening to our skin?</h2>
<p>The top layer of our skin (the stratum corneum) is our skin’s key protective layer. But frequent hand washing with repetitive exposure to water, soap and skin cleansers <a href="https://www.sciencedirect.com/science/article/pii/S0022202X15301676">will disrupt</a> this layer.</p>
<p>Over time, this leads to dry skin, further disruption of the skin barrier and inflammation. </p>
<p>This eventually results in hand dermatitis, or more specifically, <a href="https://www.dermcoll.edu.au/atoz/irritant-contact-dermatitis-icd/">irritant contact dermatitis</a>. </p>
<h2>Who’s more likely to have problems?</h2>
<p>Irritant contact dermatitis is <a href="https://www.sciencedirect.com/science/article/pii/S2093791114000560">more common</a> in people who perform “wet work” as they wash and dry their hands many times a day.</p>
<p>They include health-care workers (doctors, nurses, personal care assistants), hairdressers, food handlers, kitchen staff and cleaners. They may also be exposed to irritating skin cleansers and detergents.</p>
<p>But now handwashing is becoming more frequent during the COVID-19 pandemic, there may be more affected people outside these occupations.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/325148/original/file-20200403-74908-nwfm4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/325148/original/file-20200403-74908-nwfm4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325148/original/file-20200403-74908-nwfm4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325148/original/file-20200403-74908-nwfm4d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325148/original/file-20200403-74908-nwfm4d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325148/original/file-20200403-74908-nwfm4d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325148/original/file-20200403-74908-nwfm4d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325148/original/file-20200403-74908-nwfm4d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Health-care workers, who wash their hands multiple times a day, are particularly at risk of hand dermatitis.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/couple-surgeons-washing-hands-before-operating-633363035">Shutterstock</a></span>
</figcaption>
</figure>
<p>People with eczema, asthma and hay fever are also at <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/j.1440-0960.2007.00409.x">higher risk</a> of developing irritant contact dermatitis or experiencing a flare of underlying eczema.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/common-skin-rashes-and-what-to-do-about-them-91518">Common skin rashes and what to do about them</a>
</strong>
</em>
</p>
<hr>
<h2>How do I prevent hand dermatitis?</h2>
<p><strong>1. Soap, soap alternative or hand sanitiser?</strong></p>
<p>People with eczema or who have had contact dermatitis before will have more easily irritated skin. While they can still use hand sanitisers, it’s recommended they wash with gentler soap-free washes rather than normal soap.</p>
<p>Soap-free washes contain non-soap-based synthetic detergents (syndets). <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/jocd.12469">Syndets</a> have a nearly identical cleansing action as soap, but with the benefit of having the same pH as the skin. This means they’re less likely to remove the oils from the outer layer of the skin and are less irritating. </p>
<p>Soaps have a high pH and are <a href="https://www.egopharm.com/au/en/Hand-Hygiene-Coronavirus.html">quite alkaline</a>. This disrupts the outer layer of the skin, allowing the soap to penetrate deeper into the skin, thus causing more skin irritation and itching. </p>
<p>Other people who don’t have eczema or a history of contact dermatitis should just use soap. Liquid soaps usually contain fragrances and preservatives, which can cause another type of dermatitis (allergic contact dermatitis), so opt for a plain, unperfumed bar soap. </p>
<p><strong>2. Dry your hands thoroughly</strong></p>
<p>Dry your hands thoroughly, including the webs of your fingers and under your
rings to reduce dermatitis caused by trapped water. Skin irritation and breakdown can occur when there is excessive moisture, soap residues and water trapped between the skin and underneath rings.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/coronavirus-and-handwashing-research-shows-proper-hand-drying-is-also-vital-132905">Coronavirus and handwashing: research shows proper hand drying is also vital</a>
</strong>
</em>
</p>
<hr>
<p><strong>3. Use non-fragranced moisturiser regularly</strong></p>
<p>Moisturisers come in different formulations. While lotions are light in consistency and convenient to use during the day, they will require more frequent applications. Creams and ointments have thicker and oilier texture, are effective for dry hands and are <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ddg.12510_1">best used overnight</a>.</p>
<p>Fragrances can cause allergic contact dermatitis and are best avoided, where possible.</p>
<p><strong>4. Use alcohol-based hand sanitiser (if you can get hold of it)</strong></p>
<p>Alcohol-based hand sanitiser will reduce your skin’s contact with water, and so lower your risk of dermatitis.</p>
<p>Research in health-care workers <a href="https://www.jstage.jst.go.jp/article/indhealth/45/5/45_5_645/_article/-char/ja/">shows</a> hand sanitisers cause less contact dermatitis than washing with soap and water.</p>
<p>Sometimes people wrongly believe that when hand sanitiser stings on a paper cut, this means that they are allergic. But this is an irritant reaction and though uncomfortable, it’s safe to keep using it.</p>
<p>Which sanitiser? This usually comes down to personal preference (and what you can get hold of).</p>
<p><strong>5. Use gloves</strong></p>
<p>Use protective gloves when doing household chores, such as washing the dishes or when gardening. </p>
<p>Use cotton gloves when doing dry work, such as sweeping or dusting, to protect your hands and <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ddg.12510_1">minimise the need to wash them</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/325152/original/file-20200403-99325-co1vxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/325152/original/file-20200403-99325-co1vxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/325152/original/file-20200403-99325-co1vxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/325152/original/file-20200403-99325-co1vxh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/325152/original/file-20200403-99325-co1vxh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/325152/original/file-20200403-99325-co1vxh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/325152/original/file-20200403-99325-co1vxh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/325152/original/file-20200403-99325-co1vxh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Use washing up gloves where possible.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-washing-dishes-kitchen-close-hand-518530291">Shutterstock</a></span>
</figcaption>
</figure>
<p>At night, moisturise your hands than wear cotton gloves. This acts like an intensive hand mask and works wonders for very dry skin. It ensures the moisturiser stays on your hands and increases its penetration into your skin.</p>
<h2>What if my hands are already damaged, dry or cracking?</h2>
<p><strong>1. Act early</strong></p>
<p>Treat hand dermatitis as soon as it occurs, otherwise it will get worse. </p>
<p><strong>2. Apply petroleum jelly</strong></p>
<p>If you think you’ve lost your nail cuticle (the protective barrier between the nail and nail fold), water will be able to seep into the nail fold, causing swelling and dermatitis. </p>
<p>Use petroleum jelly, such as Vaseline, as a sealant to prevent further water damage. Petroleum jelly can also be used on skin cracks for the same reason. </p>
<p><strong>3. Seek medical help</strong></p>
<p>If there are any red, dry and itchy areas, indicating active dermatitis, seek help from your GP or dermatologist.</p>
<p>They can start you on a short burst of an ointment that contains corticosteroids until the rash subsides.</p>
<p>Prescription ointments are likely to be more effective than over-the-counter creams because of their higher potency. </p>
<p>But you could start with buying 1% hydrocortisone ointment, not cream, from the chemist.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-can-you-use-a-telehealth-consult-for-and-when-should-you-physically-visit-your-gp-135046">What can you use a telehealth consult for and when should you physically visit your GP?</a>
</strong>
</em>
</p>
<hr>
<p>Sometimes dermatitis can become infected with skin bacteria such as <em>Staphylococcus aureus</em>. Seek medical advice if you experience symptoms such as persistent soreness or pain.</p>
<p>You should also seek medical help if you have severe hand dermatitis not responding to home treatments.</p>
<p>Most GPs and dermatologists are moving to or have started using telehealth so you can consult them using a video call, minimising face-to-face appointments.</p><img src="https://counter.theconversation.com/content/134146/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Celestine Wong is a Consultant Dermatologist working at the Patch testing Clinic at Monash Medical Centre and the Royal Melbourne Hospital.</span></em></p><p class="fine-print"><em><span>Rosemary Nixon is the Director, Occupational Dermatology Research and Education Centre, Skin Health Institute, Melbourne. The centre is a not-for-profit dermatology centre affiliated with Melbourne and Monash universities. As well as her affiliation with the University of Melbourne, Rosemary Nixon is an Adjunct Clinical Associate Professor at Monash University.</span></em></p>You can prevent your skin becoming dry and inflamed with some simple steps. And if you do develop dermatitis, it’s important to seek early medical help.Celestine Wong, Consultant Dermatologist, Monash HealthRosemary Nixon, Honorary Clinical Associate Professor, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/956272018-05-07T10:42:29Z2018-05-07T10:42:29ZMaking a cleaner, greener, environmentally safe sunscreen<figure><img src="https://images.theconversation.com/files/217162/original/file-20180502-153873-1d823dg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ingredients in many sunscreens are bleaching coral and harming marine life.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/success?u=http%3A%2F%2Fdownload.shutterstock.com%2Fgatekeeper%2FW3siZSI6MTUyNTI1Nzc1NCwiYyI6Il9waG90b19zZXNzaW9uX2lkIiwiZGMiOiJpZGxfMjg1MjQ2ODcyIiwiayI6InBob3RvLzI4NTI0Njg3Mi9odWdlLmpwZyIsIm0iOjEsImQiOiJzaHV0dGVyc3RvY2stbWVkaWEifSwiT3F4YWlKWWVaYnMzdlBYU2JFQ1dET1c4TnI4Il0%2Fshutterstock_285246872.jpg&pi=33421636&m=285246872&src=X9DiWRrCW1zryS-cTr8A1g-2-8">www.shutterstock.com</a></span></figcaption></figure><p>As the temperatures rise and Americans swarm to the beach, they slather on sunscreen to protect against the sun’s harmful UV radiation that causes <a href="https://www.cdc.gov/cancer/skin/statistics/index.htm">skin cancer</a>. As they splash and swim, few give thought to whether the chemicals in the lotions and sprays are safe for marine organisms such as the fish and corals living in these coastal zones. </p>
<p>The bad news is that mounting evidence suggests that certain chemicals in these radiation filters are bleaching the corals and killing fish. The good news is that there is a greener, cleaner and safer alternative in the works. </p>
<p>The sunscreens widely available belong to two major categories: physical and chemical. Physical sunscreens contain tiny minerals that act as a shield deflecting the sun’s rays. On the other hand, <a href="https://doi.org/10.1016/j.jaad.2016.09.038">chemical sunscreens</a> use many synthetic compounds that absorb UV light before it reaches the skin. </p>
<h2>Killer chemicals</h2>
<p>But these lotions wash off in water. For example, for every 10,000 visitors frolicking in the waves, about <a href="http://doi.org/10.1021/es5020696">4 kilograms of mineral particles are washed into the beach water each day</a>. These minerals catalyze the production of hydrogen peroxide, a well-known bleaching agent, at a concentration high enough to harm coastal marine organisms. In fact, up to 14,000 tons of sunscreens are released into the water each year. <a href="https://doi.org/10.1007/s00244-015-0227-7">Active ingredients in these sunscreens</a>, minerals and synthetic organic compounds, are putting 10 percent of the global reefs under stress, including 40 percent of coral reefs along the coast. </p>
<p>One of these ingredients is oxybenzone, a synthetic molecule commonly used in chemical sunscreens and known to be <a href="http://doi.org/10.1289/ehp.10966">toxic to corals</a>, algae, sea urchins, fish and mammals: A single drop of this compound in over 4 million gallons of water is already enough to endanger organisms. Unfortunately, its <a href="https://doi.org/10.1007/s00244-015-0227-7">concentration in coastal water</a> is already significantly higher than its toxic limit, though not yet deadly, and might be accelerating <a href="http://doi.org/10.1126/science.1085046">coral bleaching</a>. To save their marine ecosystem from further destruction, legislators in Hawaii passed a new <a href="https://www.capitol.hawaii.gov/measure_indiv.aspx?billtype=SB&billnumber=2571&year=2018">law</a> banning chemical sunscreens containing oxybenzone and another harmful ingredient, octinoxate. The law will take effect January 1, 2021.</p>
<h2>Sunscreen from algae</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/217348/original/file-20180502-153888-ea8324.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/217348/original/file-20180502-153888-ea8324.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/217348/original/file-20180502-153888-ea8324.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/217348/original/file-20180502-153888-ea8324.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/217348/original/file-20180502-153888-ea8324.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/217348/original/file-20180502-153888-ea8324.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/217348/original/file-20180502-153888-ea8324.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A flask of the cyanobacterium Synechocystis sp. PCC 6803 that was used to produce shinorine. The green color comes from the chlorophyll, which is a natural part of the bacterium. Shinorine is clear.</span>
<span class="attribution"><span class="source">Dr. Guang Yang</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Protecting ourselves from UV rays is nothing new. Many organisms including microbes, plants and animals have evolved ways to guard themselves. These organisms produce <a href="https://doi.org/10.1111/j.1469-185X.1999.tb00189.x">small molecules that absorb UV rays</a> and block radiation from entering cells and damaging the DNA. Unlike physical and synthetic chemical sunscreens, these naturally available compounds are environmentally friendly and biodegradable. As such, these natural products have the potential to be safer compounds for commercial sunscreens. </p>
<p>In my laboratory in the College of Pharmacy at the University of Florida, we are interested in combing the world for naturally occurring chemicals that have applications in health, agriculture and environment. Recently, my colleagues and I have discovered <a href="http://doi.org/10.1021/acssynbio.7b00397">a more efficient way to harvest shinorine</a> – a natural sunscreen produced by microbes called cyanobacteria. </p>
<p><a href="https://pubchem.ncbi.nlm.nih.gov/compound/101926676#section=Top">Shinorine</a> belongs to a family of natural products, called mycosporine-like amino acids, and is made up of two amino acids and one sugar. Many aquatic organisms exposed to strong sunlight, like cyanobacteria and macroalgae, produce shinorine and other related compounds to protect themselves from solar radiation. The cosmetics industry is already infusing products with shinorine as a key active ingredient. Commercial supplies of shinorine come from marine red algae that grows slowly in large tidal pools that experience frequent environmental changes. That means that conventional extraction method is time-consuming and unpredictable. </p>
<p>To ramp up shinorine production, we sought a fast-growing strain of cyanobacteria that would thrive under predictable conditions. This took a lot of work! We decoded the genetic blueprints – genomes – of more than 100 varieties of cyanobacteria from marine and terrestrial ecosystems and selected one, <em>Fischerella</em> sp. PCC9339, to cultivate in the laboratory. </p>
<p>To our delight, after four weeks this strain produced shinorine, but unfortunately not enough. To produce more we then transferred a set of genes that encode the instructions to make shinorine, into one freshwater cyanobacterium (from Berkeley, California), <em>Synechocystis</em> sp. PCC 6803, which grows fast with just water, carbon dioxide and sunlight. Using the engineered cyanobacterium, we produced a quantity of shinorine comparable to the conventional method – but we did it in just a few weeks instead of one year that’s needed to cultivate red algae. </p>
<p>By advancing the method to produce more shinorine and other UV-absorbing natural products, we hope to make “green” sunscreens more available – to protect our skin and the lives of the creatures we are so eager to see.</p><img src="https://counter.theconversation.com/content/95627/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Yousong Ding does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Scientists have discovered a natural sunscreen – made by microbes – that may be better for humans and the marine critters they are hoping to see.Yousong Ding, Assistant Professor of Medicinal Chemistry, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/743552017-05-26T01:32:59Z2017-05-26T01:32:59ZHow do the chemicals in sunscreen protect our skin from damage?<figure><img src="https://images.theconversation.com/files/171062/original/file-20170525-23230-m46xg5.jpg?ixlib=rb-1.1.0&rect=0%2C98%2C2000%2C1419&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Don't skimp on the SPF.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/toned-photo-kid-beach-smooth-skin-381581356">Sabphoto via Shutterstock.com</a></span></figcaption></figure><p>Not so long ago, people like my Aunt Muriel thought of sunburn as a necessary evil on the way to a “good base tan.” She used to slather on the baby oil while using a large reflector to bake away. Aunt Muriel’s mantra when the inevitable burn and peel appeared: Beauty has its price.</p>
<p>Was she ever right about that price – but it was a lot higher than any of us at the time recognized. What sun addicts didn’t know then was that we were setting our skin up for damage to its structural proteins and DNA. Hello, wrinkles, liver spots and cancers. No matter <a href="https://doi.org/10.1001/archderm.1988.01670060015008">where your complexion falls</a> on the <a href="http://www.skincancer.org/prevention/are-you-at-risk/fitzpatrick-skin-quiz">Fitzpatrick Skin Type</a> scale, ultraviolet radiation (UV) from the sun or tanning beds will damage your skin.</p>
<p>Today, recognition of the risks posed by UV rays has motivated scientists, myself included, to study what’s going on in our cells when they’re in the sun – and devise modern ways to ward off that damage.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/170967/original/file-20170525-23279-110s6q8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/170967/original/file-20170525-23279-110s6q8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/170967/original/file-20170525-23279-110s6q8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=236&fit=crop&dpr=1 600w, https://images.theconversation.com/files/170967/original/file-20170525-23279-110s6q8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=236&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/170967/original/file-20170525-23279-110s6q8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=236&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/170967/original/file-20170525-23279-110s6q8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=297&fit=crop&dpr=1 754w, https://images.theconversation.com/files/170967/original/file-20170525-23279-110s6q8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=297&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/170967/original/file-20170525-23279-110s6q8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=297&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">UV light that affects our skin has a shorter wavelength than the parts of the electromagnetic spectrum we can see.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:EM_Spectrum_Properties_edit.svg">Inductiveload, NASA</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>What happens when sun hits skin</h2>
<p>Sunlight is composed of packets of energy called photons. The visible colors we can see by eye are relatively harmless to our skin; it’s the sun’s ultraviolet (UV) light photons that can cause skin damage. UV light can be broken down into two categories: UVA (in the wavelength range 320-400 nanometers) and UVB (in the wavelength range 280–320 nm). </p>
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<p>Our skin contains molecules that are perfectly structured to absorb the energy of UVA and UVB photons. This puts the molecule into an energetically excited state. And as the saying goes, what goes up must come down. In order to release their acquired energy, these molecules undergo chemical reactions – and in the skin that means there are biological consequences.</p>
<p>Interestingly, some of these effects used to be considered helpful adaptations – though we now recognize them as forms of damage. Tanning is due to the production of <a href="https://www.derm101.com/inflammatory/embryologic-histologic-and-anatomic-aspects/melanocytes/">extra melanin pigment induced by UVA rays</a>. Exposure to the sun also turns on the skin’s natural antioxidant network, which <a href="http://www.nature.com/nchembio/journal/v10/n7/pdf/nchembio.1548.pdf">deactivates highly destructive reactive oxygen species (ROS) and free radicals</a>; if left unchecked, these can cause cellular damage and oxidative stress within the skin.</p>
<p>We also know that UVA light penetrates deeper into the skin than UVB, destroying a structural protein called collagen. As collagen degrades, our skin loses its elasticity and smoothness, leading to wrinkles. UVA is responsible for many of the visible signs of aging, while UVB light is considered the primary source of sunburn. Think “A” for aging and “B” for burning.</p>
<p>DNA itself can absorb both <a href="http://www.pnas.org/content/103/37/13765.short">UVA and UVB rays, causing mutations</a> which, if unrepaired, can lead to non-melanoma (basal cell carcinoma, squamous cell carcinoma) or <a href="https://doi.org/10.1126/science.1253735">melanoma skin cancers</a>. Other skin molecules pass absorbed UV energy on to those highly reactive ROS and free radicals. The resulting oxidative stress can overload the skin’s built-in antioxidant network and cause cellular damage. ROS can react with DNA, forming mutations, and with collagen, leading to wrinkles. They can also interrupt cell signaling pathways and gene expression.</p>
<p>The end result of all of these photoreactions is photodamage that accumulates over the course of a lifetime from repeated exposure. And – this cannot be emphasized enough — this applies to all skin types, from Type I (like Nicole Kidman) to Type VI (like Jennifer Hudson). <a href="http://www.skincancer.org/skin-cancer-information/skin-cancer-facts">Regardless of how much melanin we have in our skin</a>, we can develop UV-induced skin cancers and we will all eventually see the signs of photo-induced aging in the mirror.</p>
<h2>Filtering photons before the damage is done</h2>
<p>The good news, of course, is that the risk of skin cancer and the visible signs of aging can be minimized by preventing overexposure to UV radiation. When you can’t avoid the sun altogether, today’s sunscreens have got your back (and all the rest of your skin too).</p>
<p>Sunscreens employ UV filters: molecules specifically designed to help reduce the amount of UV rays that reach through the skin surface. A film of these molecules forms a protective barrier either absorbing (chemical filters) or reflecting (physical blockers) UV photons before they can be absorbed by our DNA and other reactive molecules deeper in the skin. </p>
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<p>In the United States, the Food and Drug Administration regulates sunscreens as drugs. Because we were historically most concerned with protecting against sunburn, <a href="http://dx.doi.org/10.1016/j.jaad.2010.01.005">14 molecules that block sunburn-inducing UVB rays</a> are approved for use. That we have just two UVA-blocking molecules available in the United States – avobenzone, a chemical filter; and zinc oxide, a physical blocker – is a testament to our more recent understanding that UVA causes trouble, not just tans.</p>
<p>The FDA also has enacted <a href="https://www.federalregister.gov/documents/2011/06/17/2011-14766/labeling-and-effectiveness-testing-sunscreen-drug-products-for-over-the-counter-human-use">strict labeling requirements</a> – most obviously about SPF (sun protection factor). On labels since 1971, SPF represents the relative time it takes for an individual to get sunburned by UVB radiation. For example, if it takes 10 minutes typically to burn, then, if used correctly, an SPF 30 sunscreen should provide 30 times that – 300 minutes of protection before sunburn. </p>
<p>“Used correctly” is the key phrase. Research shows that it takes about one ounce, or basically a <a href="https://www.aad.org/media/stats/prevention-and-care/sunscreen-faqs">shot glass-sized amount of sunscreen</a>, to cover the exposed areas of the average adult body, and a nickel-sized amount for the face and neck (more or less, depending on your body size). The majority of people apply between a <a href="https://www.ncbi.nlm.nih.gov/pubmed/12374537">quarter to a half of the recommended amounts</a>, placing their skin at risk for sunburn and photodamage.</p>
<p>In addition, sunscreen efficacy decreases in the water or with sweating. To help consumers, FDA now requires sunscreens labeled <a href="https://www.federalregister.gov/documents/2011/06/17/2011-14766/labeling-and-effectiveness-testing-sunscreen-drug-products-for-over-the-counter-human-use">“water-resistant” or “very water-resistant”</a> to last up to 40 minutes or 80 minutes, respectively, in the water, and the <a href="https://www.aad.org/media/stats/prevention-and-care/sunscreen-faqs">American Academy of Dermatology</a> and other medical professional groups <a href="https://www.cancer.org/cancer/skin-cancer/prevention-and-early-detection/uv-protection.html">recommend reapplication immediately after any water sports</a>. The general <a href="https://www.aad.org/media/stats/prevention-and-care/sunscreen-faqs">rule of thumb</a> is to reapply about every two hours and certainly after water sports or sweating.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171063/original/file-20170525-23234-v4lxdi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171063/original/file-20170525-23234-v4lxdi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171063/original/file-20170525-23234-v4lxdi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171063/original/file-20170525-23234-v4lxdi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171063/original/file-20170525-23234-v4lxdi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171063/original/file-20170525-23234-v4lxdi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=565&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171063/original/file-20170525-23234-v4lxdi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=565&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171063/original/file-20170525-23234-v4lxdi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=565&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In the U.S., the FDA regulates sunscreens available to consumers.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/alameda-ca-june-05-2016-store-433399849">Sheila Fitzgerald via Shutterstock.com</a></span>
</figcaption>
</figure>
<p>To get high SPF values, multiple UVB UV filters are combined into a formulation based upon <a href="https://www.federalregister.gov/documents/2011/06/17/2011-14766/labeling-and-effectiveness-testing-sunscreen-drug-products-for-over-the-counter-human-use">safety standards set by the FDA</a>. However, the SPF doesn’t account for UVA protection. For a sunscreen to make a claim as having UVA and UVB protection and be labeled “Broad Spectrum,” it must pass <a href="https://www.fda.gov/drugs/guidancecomplianceregulatoryinformation/guidances/ucm330694.htm">FDA’s Broad Spectrum Test</a>, where the sunscreen is hit with a large dose of UVB and UVA light before its effectiveness is tested. </p>
<p>This pre-irradiation step was established in <a href="https://www.fda.gov/drugs/guidancecomplianceregulatoryinformation/guidances/ucm330694.htm">FDA’s 2012 sunscreen labeling rules</a> and acknowledges something significant about UV-filters: some can be photolabile, meaning they can degrade under UV irradiation. The most famous example may be <a href="http://onlinelibrary.wiley.com/doi/10.1046/j.1440-0960.1999.00319.x/full">PABA</a>. This UVB-absorbing molecule is rarely used in sunscreens today because it forms photoproducts that elicit an allergic reaction in some people.</p>
<p>But the Broad Spectrum Test really came into effect only once the UVA-absorbing molecule avobenzone came onto the market. Avobenzone can interact with octinoxate, a strong and widely used UVB absorber, in a way that makes avobenzone less effective against UVA photons. The UVB filter octocrylene, on the other hand, helps stabilize avobenzone so it lasts longer in its UVA-absorbing form. Additionally, you may notice on some sunscreen labels the molecule ethylhexyl methoxycrylene. It helps stabilize avobenzone even in the presence of octinoxate, and provides us with longer-lasting protection against UVA rays.</p>
<p>Next up in sunscreen innovation is the broadening of their mission. Because even the highest SPF sunscreens don’t block 100 percent of UV rays, the addition of antioxidants can supply a second line of protection when the skin’s natural antioxidant defenses are overloaded. Some antioxidant ingredients my colleagues and I have worked with include <a href="http://www.springer.com/us/book/9783319293813">tocopheral acetate (Vitamin E), sodium ascorbyl phosophate (Vitamin C), and DESM</a>. And sunscreen researchers are beginning to investigate if the <a href="http://www.springer.com/us/book/9783319293813">absorption of other colors of light</a>, like infrared, by skin molecules has a role to play in photodamage.</p>
<p>As research continues, one thing we know for certain is that protecting our DNA from UV damage, for people of every color, is synonymous with preventing skin cancers. The Skin Cancer Foundation, American Cancer Society and the American Academy of Dermatology all stress that research shows regular use of an SPF 15 or higher sunscreen prevents sunburn and reduces the risk of <a href="http://dx.doi.org/10.1016/S0140-6736(98)12168-2">non-melanoma cancers by 40 percent</a> and <a href="https://doi.org//10.1200/jco.2010.28.7078">melanoma by 50 percent</a>.</p>
<p>We can still enjoy being in the sun. Unlike my Aunt Muriel and us kids in the 1980s, we just need to use the resources available to us, from long sleeves to shade to sunscreens, in order to protect the molecules in our skin, especially our DNA, from UV damage.</p><img src="https://counter.theconversation.com/content/74355/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kerry Hanson has consulted for Bayer, J&J/Neutrogena, and P&G. Her academic work has been funded by Hallstar and through a joint University of California Discovery Grant with Merck. She is a member of the American Chemical Society. </span></em></p>Energy from the sun’s rays can cause skin damage and cancers. Sunscreens can absorb or reflect the dangerous UV light. Here’s how it works.Kerry Hanson, Research Chemist, University of California, RiversideLicensed as Creative Commons – attribution, no derivatives.