Ep 34: Dermatologist’s Guide to Sunscreen
Dr. TWL: Hi guys, welcome to today’s episode of Dermatologist talks: Science of Beauty. I’m Dr Teo Wan Lin of TWL Specialist Skin & Laser Centre and in this week’s episode, we’re going to talk about what makes an ideal sunscreen and how to choose the best sunscreen for your skin.
Chelsea: You may know by now that sunscreen is a must-have in any skincare routine. However, you may not know all the reasons why it’s so important.
Apart from preventing a bad sunburn, can you share with us why sunscreen is so essential?
Dr. TWL: Sunscreen itself performs a fundamental role of protecting your skin from damaging ultraviolet radiation. Both UVA and UVB have been implicated in photoaging. As well as in carcinogenesis, which is a process of skin cancer formation. Simply put, when we have ultraviolet radiation exposure, as we grow older, our skin becomes less and less able to handle the oxidative stress and the ensuing free radical generation. All of which permit DNA damage to occur at the cellular level.
This DNA damage becomes what we now call the visible signs of skin aging. We often refer to the Glogau photoaging scale to determine the stage of photoaging. This scale measures the depth of your wrinkles, skin elasticity, and dermal fullness which is responsible for the skin appearance being plump and radiant. The presence of skin atrophy, textural irregularities and hyperpigmentation. These are all the signs we associate with ageing and is also in the Glogau photoaging scale. More than this, as dermatologists, we are particularly aware of the direct influence of ultraviolet radiation on the development of skin cancers.
Living in in a tropical climate, does that mean we have a higher risk of these harmful effects of sun exposure?
Dr. TWL: Living in Singapore which has a year-round tropical climate, and being right at the equator, we have maximum ultraviolet radiation exposure. We are certainly at risk of being the recipients of damaging ultraviolet rays. Also, in terms of cumulative sun exposure. In Singapore, the overall incidence of skin cancer has been increasing throughout the years.
Chelsea: I do know that due to the amount of photoprotective melanin in our skins, Asians and skin of color do tend to have fewer signs of aging.
Does that mean we do not need as much sun protection, or can look for sunscreens that are lower in SPF?
Dr. TWL: Asians belong to the category of skin of color. Therefore, we have inherent protection against ultraviolet radiation. This explains to a certain degree why we observe fewer signs of photoaging in skin of colour individuals. This is comparing to their Caucasian counterparts who are of the same biological age. I feel that it is very important, though, to not mistake that for actually having a reduced risk of skin cancer and hence throw caution to the wind and believe that we can go without sunscreen or other sun-protective measures.
Traditionally, we do emphasize that the high-risk group of skin cancer patients would be those who have fair skin, have light color eyes, reddish or blond hair, and of course, with a family history of skin cancers. Non-melanoma skin cancers, in particular, are rather prevalent in an Asian population like in Singapore. Especially in the older age group as cumulative sun exposure can also affect this.
Actinic keratosis, for example, we often ignore it because it looks fairly benign. It appears as red flaky bumps on the skin that sometimes it’s even observed to disappear on its own. In fact, these are pre-cancerous forms of skin lesions, known as squamous cell cancer. Therefore, it’s very very important to pick up these symptoms for monitoring.
Chelsea: We can definitely see the importance of sunscreen for our overall skin health.
Apart from sunscreen, are there any other ways we can protect our skin from the damaging effects of sun exposure?
Dr. TWL: Now, going onto the topic of photoprotection. Sunscreen obviously is our main weapon against sun-induced damage. But before we go in-depth into sunscreen, we’re going to talk about sun avoidance behavior which is a huge part. In fact, I consider it as even more important than the application of sunscreen. It’s important to note that for typical hours of 9am to maybe 4pm, and that’s what’s reported in the Western latitudes to have the highest doses of this ultraviolet radiation reaching the earth’s surface. For us, being at an equatorial location, we would actually recommend avoiding the sun even much earlier in the day and all the way till it’s much later in the evening.
Sun avoidance behavior can also come in the form of ultraviolet protective clothing. Such as long-sleeved clothing, especially for those involved in outdoor sports. Additionally, wearing broad-brimmed hats that provide some shade over the facial area can help. Other sun avoidance behavior includes discouraging sunbathing behavior, which is somewhat trendy in climates with summer weather where people like to go to the beach and tan. It is very important that we discourage that in Singapore because sun protection is not just about preventing photoaging. Instead, it’s more important to know that it can directly affect your health and cause skin cancer. For example, melanoma can occur in Asians as well.
Chelsea: So we do still have to be vigilant when it comes to sun protection. Well I’m aware that there are two main types of sunscreen: physical and chemical. Physical sunscreen creates a barrier on skin that reflects and scatters UV rays away from the skin. Chemical sunscreen absorbs into the skin, converting UV rays into heat.
How do I tell which sunscreen is right for me?
This sunscreen is formulated with physical blockers like titanium dioxide and zinc oxide that effectively blocks UV radiation. Portulaca Oleracea (Purslane) and Oligopeptides in our SunProtector are potent antioxidants which actively fight free radicals generated by UV exposure as well as airborne pollutants – for comprehensive protection.
Dr. TWL: Going into the topic of sunscreen, I would say that sunscreen itself has been evolving significantly over the last decade in terms of cosmetic science technology over the last decade. Traditionally for individuals who have sensitive skin, eczema or other types of skin disease, dermatologists recommend physical blockers – such as those containing zinc oxide or titanium dioxide-base sunscreens. We deem these to be less reactive on sensitive skin.
However, the cosmetic problem with these sunscreens is that it tends to leave a white cast over skin. This is very relevant if you’re talking about skin of color populations like in Asia. The other bugbear in sunscreen formulation is the concept of UVA protection. This is very relevant when you’re talking about prevention of photoaging in particular.
Chemical sunscreens, Avobenzones- these are important components of a good sunscreen. However, the thing with chemical sunscreens is that they associate with less tolerability, especially in sensitive skin individuals. This really has to do with not just the overall formulation and the mix of the ingredients, but the fact that it is mixed with sweat, you would find that sensitive skin patients have sweat allergies. Because of skin barrier dysfunction, the perceived irritation from the chemical sunscreen component can be highlighted.
Something to consider is that you’ll actually find it quite rare to have true allergy or irritation from sunscreen – even from the chemical component. Rather, if you have sensitive skin in general, you’re just much more prone to have reduced tolerability because of barrier dysfunction and in outdoor conditions when you sweat. Because, there is an inherent tendency for eczema patients to have sweat allergies as well.
That being said, a lot of dermatologists still prefer to use pure physical blockers for patients with eczema. However, I personally feel are very impractical when you apply it on the face. Because of the white cast and some individuals may be sensitive to the smell. In this case, we do prioritize compliance. So if it’s not cosmetically appealing, then it’s something for us to address.
Chelsea: Ah that makes sense! For me, since I have combination skin, I like to use a chemical sunscreen since I find that they make my skin feel less greasy. But I do find that they can sometimes irritate my skin. I didn’t know that there were sunscreens that could incorporate both – so I definitely need to be on the lookout for that.
Korean sunscreen controversy
Dr. TWL: Now the second thing we’re going to talk about is the SPF rating of sunscreens. Something that has gained quite a lot of attention in the last couple of months, especially in the media, was the issue with Korean sunscreens. It started with a report from the founder of the INCIDecoder website, Judit Racz. In December 2020, she published data from two European Sun Protection Laboratories, about Korean sunscreen Purito, which actually showed that the sunscreen was only at SPF 19 as opposed to the SPF 50 that was declared. The incident was flagged up to the kFDA. Broader investigations revealed that it indeed had certain shortfalls with regards to the sun protection factor.
Chelsea: I heard about that! This incident really cast a lot of doubt on beauty product labels, and made many wonder if SPF Ratings could still be trusted.