How much sun cream should I use? "Men are more likely to be sunbathers"
Nowhere else in Europe do as many men get black skin cancer as in Switzerland. A dermatologist talks about highly dangerous beauty ideals, UV protection for the office and questionable ingredients in sun creams.
People who spend time outdoors have around a 19-fold lower risk of contracting the novel coronavirus. This is suggested by a recent preprint study from Japan.
However, we should not take the particularly strong UV radiation at this time of year lightly. We found out from dermatologist Prof. Dr. Dr. med. Antonio Cozzio what years of intensive sun exposure do to our skin and why there is a risk of skin damage even in the office.
Mr. Cozzio, did you apply sunscreen this morning?
Now you've caught me out with the first question. No, not today - but I usually do, and it makes sense.
Even though you, like most other professionals, are indoors during the day?
Only the UV-B rays, which can cause acute damage such as sunburn, are mostly blocked by glass. UV-A rays are different: They penetrate window panes and damage the DNA of skin cells, which can later lead to the development of skin cancer. In addition, the skin ages faster when we expose it to UV light.
Even when it is cloudy and rainy ...
UV-A rays cannot be blocked even by thick cloud cover; as long as the day is bright, UV rays will reach the earth as well as light rays.
The importance of effective sun protection, even in cloudy weather, is particularly evident in immunosuppressed patients: due to an autoimmune disease or after an organ transplant, they have to be treated with medication that shuts down the immune system. As a result, they have a 60 to 200 times higher risk of developing light skin cancer than healthy people.
About the person: Antonio Cozzio
Picture: zVg
Some sun protection products contain substances such as benzophenones, which can trigger allergies and are suspected of influencing the body's hormone system. Are there safer alternatives?
Unlike in the USA, for example, in Europe attempts are largely being made to avoid UV filters of the benzophenone-3 group, which can be contained in products with chemical UV filters. However, the findings to date on hormonal effects are based solely on animal studies in which rats were administered large quantities of such substances through their food, i.e. not through the skin. Nevertheless, we recommend sun protection with a physical filter for children.
What is the difference between a chemical and a physical UV filter?
While the chemical UV filter is absorbed into the skin and develops its protective function around 20 minutes after application, physical sun protection works by means of small, reflective particles on the skin. Protection is provided immediately after applying the cream. However, the disadvantage is that it can whiten the skin, making it appear much lighter than it actually is.
On the other hand, you can see immediately where you have already applied cream and where you still need to reapply. However, another advantage of many physical sunblocks is that they can also reflect the blue light visible to the eye, which is also part of the sunlight spectrum and can also damage the skin.
Which sun protection factor makes sense?
I recommend a sun protection product with a high sun protection factor, preferably 50, but not less than 30. Experience has shown that the factor is reduced if the cream is applied far too thinly. If you then sweat, you will soon no longer be at factor 50, but rather at 30. After bathing, I would recommend reapplying cream.
If you've already spent two hours in the sun, it's not worth reapplying: it's better to spend the rest of the day in the shade. Sun creams are designed to protect us from the sun, but they should not encourage us to stay in the sun for longer.
The hormone vitamin D is produced by the body itself as a result of sun exposure. Isn't there a risk of vitamin D deficiency due to excessive sun protection?
Absolutely perfect sun protection prevents UV-B radiation from reaching the skin, which means that the body can hardly produce vitamin D itself. This would be the case, for example, if someone lived a complete day/night reversal - sleeping in the dark during the day and being active at night. So much for the theory.
What is much more realistic is that you are not completely protected from the sun everywhere and at all times: In summer, it only takes a few minutes of sun exposure on a small area of the body, such as the face or hands, to produce enough vitamin D. Vitamin D is important for the function of various processes in the body, such as the immune system.
Whether it is available in sufficient quantities can be determined by having a blood test carried out by a doctor. If there is a deficiency, this can simply be remedied with vitamin D drops. This makes more sense than risking skin damage or , in the worst case, skin cancer through artificially prolonged exposure to the sun.
On the other hand, a lack of sun exposure will result in the still unpopular "office pallor" ...
Unfortunately, this is still the perception in society: being tanned appears to be particularly cool. However, the so-called "healthy tan" is nothing more than a dangerous myth. The tanning of the skin is a sign that UV radiation has caused a defect in the skin's genetic material.
This is nothing more than a cry for help from the skin cells: The tanning effect occurs because melanin is produced in the skin - the cell tries to protect and cover the cell nucleus from further damage with this pigment. Any tanning is therefore nothing more than a sign of skin damage.
Nowhere in Europe are as many men affected by black skin cancer as in Switzerland. Are men generally more cautious, less careful than women when it comes to sun protection?
Yes, this is also in line with my experience: in general, men tend to be more reluctant to use sunscreen. I could personally imagine that many of them simply find applying sunscreen too much of a hassle.
The perception of doing something good for themselves and looking after themselves is also not so important for many men, at least not for those of my generation. However, I believe that there is a certain change in thinking among younger men: They are more likely to take care of their skin and protect it better from the sun.
If your skin has been exposed to the sun for years and you have had one or more sunburns in the past, how do you recognize skin cancer or its preliminary stages?
You should keep an eye on any noticeable new skin spots that appear in adulthood. These can be new moles or those whose appearance changes in color, shape or size. Rough patches or scaly incrustations that can be easily scratched away and under which there is bleeding are also suspicious. This could be a white skin cancer. In any case, such skin changes should be examined by a dermatologist.
Do you think apps that allow people to take photos of conspicuous skin changes and have them assessed by specialists are useful?
I think this is a good way to get an initial professional assessment. I think it is essential that the quality of the photos, i.e. their resolution, allows a dermatologist's assessment. However, these apps also have their limits, because only in dermatology practices are all areas of the skin examined. Many of the things that laypeople notice are actually completely harmless. Conversely, some skin spots may appear harmless even though they are cancerous or precancerous.
How often do you recommend a medical skin cancer check?
That also depends on the individual's medical history. If you have already been diagnosed with skin cancer - either yourself or a close relative - we recommend at least an annual check-up. We also advise people who are immunosuppressed, who have more than 100 moles or who were exposed to particularly intense sunlight during childhood or adolescence. Some of these patients may need to visit the dermatologist several times a year.
Apart from UV radiation, are there other factors that influence our risk of skin cancer?
In dermatology, we also summarize such external or extrinsic influences under the term (skin) exposome. This refers to factors such as oxidative stress, climatic conditions, diet or tobacco and alcohol consumption. We still know relatively little about the intrinsic aspects, i.e. everything that we bring with us genetically.
We do know of some mutations and DNA repair enzyme defects in which skin cancers occur much more frequently than in people with unaltered gene variants. These mutations can have an influence on the development of melanoma, i.e. black skin cancer, even without further exposure to sunlight, because sometimes, albeit rarely, it develops in places that are not exposed to any UV radiation. For example, in the gastrointestinal tract or vaginal area.
What is the treatment if a melanoma is discovered during an examination?
First, the cancer is surgically removed. This is usually a minor procedure under local anesthesia. If it is a melanoma, further examinations must be carried out to determine whether metastases have already formed in the body. In the past, the prognosis for metastatic melanoma was very unfavorable.
New treatments such as immunotherapies or targeted therapies have significantly improved the prospects for patients. However, the best chance of a cure is if the skin cancer is detected before it has spread. This underlines the importance of early detection: a dermatologist should be consulted if there are any noticeable changes in the skin.
And in the case of light skin cancer?
Basal cell carcinoma only metastasizes extremely rarely. Therapies such as surgery, radiotherapy and possibly local chemotherapy are used here. This is not the case with spinocellular carcinoma, which forms metastases much more frequently.
For us dermatologists, it is becoming increasingly important that we not only solve the local problem of white skin cancer, but also treat the surrounding skin, which has often already developed early forms of skin cancer - we call this the treatment of field cancer formation (field carcinogenesis).
