Nick Lowe (Professor of Dermatology) gives expert video advice on: What are the common signs of skin cancer?; How often should I wear sunscreen?; Can I use sunscreen for the body on my face? and more...
What is a tan?
Sun tanning is tanning of the skin by sunlight or ultraviolet tanning beds. It's an attempt by the skin to protect itself from further damage. And so what happens is that the skin is badly damaged from the sun, and you get a production of melanin, which is the pigment formed in the skin that then finishes up by giving you a suntan. You get more pigment formed, more melanin formed, that produces the tan. Interestingly, if you expose very gradually to small amounts of sunlight through a sunscreen, that slowly acquired tan will last a lot longer than going out and baking in the sun. If you go out and bake in the sun, the skin cells are increased in turnover, they shed more and you'll lose your tan much more quickly. So a safe, carefully acquired tan through a sunscreen is actually a better tan. You will get only minimum protection from the sun from a tan, maybe at the maximum an SPF of about a three from a suntan. And, in fact, pale skin won't be protected much at all.
What are the effects of sun exposure on the skin?
Sunlight has a variety of harmful effects on the skin. That includes damage to the outer skin layers that can lead to skin cancer, sometimes after 10 or 20 years after the sun damage. It can lead to premature wrinkling and aging, sometimes 10 or 20 years after the sunlight exposure. In certain olive-skinned people, Mediterranean-skinned women who have had pregnancy or been on the contraceptive pill, it can lead to pigmentation or dark patches on the skin. Sunlight can do a wide variety of things. In addition, there is a small amount of sunlight that can be helpful, so very small amounts of controlled sunlight are thought to help things like reduce certain diseases such as bone thinning, osteoporosis, such as multiple sclerosis, such as certain cancers. It's thought that, for example, prostate cancer may be reduced in sunny climates but you don't need a huge amount of sunlight to get the benefits. Controlled sun exposure is one thing, but uncontrolled sun exposure will damage your skin.
What are the common signs of skin cancer?
Skin cancers may not only appear on some exposed skin. In fact, one of the most common sites for melanoma, which is a cancerous mole, is on the back of the legs, or the front of the legs in women, which is not an area that people often associate. The signs of skin cancer really are widely different, but it can be summed up by anything that scabs, bleeds, crusts, doesn't heal, or repetitively bleeds, and even that appears to heal between those bleeding episodes. If you've got a mole that has changed in any way, if it's become scaling, crusted, darker, become irregular in shape or color, or if it's a new mole that's suddenly appeared. Any of those can be the sign of a cancerous mole. If you've got a little ulcer, a break in the skin, that bleeds or crusts or is shiny, that can be a sign of squamous cell, or basal cell cancer. If you've got lots of flat, scaly spots on the face or on the back of the hands, that can be a sign of pre skin cancer, also known as silicatosis. With any of those changes, go and ask to see a dermatologist.
What is SPF?
An SPF is a statement by a sunscreen of its sun protection factor, or SPF, and it means that it's been tested to see how long you can stay out in the sun, or how long that sunscreen can prevent burning. An SPF 15 theoretically means that you can stay out in the sun 15 times longer with the sunscreen before you develop a slight sunburn.
How much sunscreen do I need?
The problem is that people don't usually apply sunscreens in a thick enough amount. You need to apply a reasonable thickness of sunscreen to know that you're getting the SPF that the sunscreen claims on its bottle or box. That means, generally, a teaspoon over the whole face and neck. It means a tablespoon over the face, the chest, and the hands.
What factor SPF should I use?
What's very important about SPF is to realize that it doesn't tell you about the anti-aging effects of a sunscreen. That is mainly the UVA protection. For example, you need to have an SPF at least of 15 for daily use and in my opinion, you need a UVA protection factor that's superior, or if you buy it from Boots, as a four-star rating or a four plus rating. That tells you if you've got an SPF 15 with a four-star rated UVA protection sunscreen, you've got broad spectrum protection. If you are sweating or perspiring, reapply your sunscreen. It doesn't matter how many times a day, usually two to three times a day is sometimes necessary.
How often should I wear sunscreen?
My advice with sunscreens is to, even in the UK between the months of March and the end of October, apply a daily sunscreen and apply it to the face, the neck, the chest and the hands. In other words, any exposed skin. If you're driving your car and you want to reduce aging, UV rays come through car windows so it will age where you don't have that sunscreen on. The sunscreen will help to reduce that. Should you apply sunscreen in the winter? You probably don't need it in northern Europe but you do if you're flying off to sunny climates like the Caribbean or Florida. Remember to take your sunscreen with you. There are some very good ones that are available. Interestingly, European sunscreens tend to be better than American sunscreens because we're not as regulated by the Food and Drug Administration as we are in the United States. Take your sunscreen from Europe if you're going to Florida.
Can I use sunscreen for the body on my face?
You can use the same sunscreen on the body as you can on the face, but some facial sunscreens are more elegant formulations to prevent you getting acne, whereas sunscreen on the body, if you're on vacation, you may want to have a waterproof sunscreen. In general, there are body sunscreens that you need to use if you're on vacation and exposed to a lot of sunlight. If you're on a normal, daily routine you can use the same sunscreen on your face, your neck, your chest and your hands.
Are sunbeds safe?
No sunbeds are safe. It's as simple a statement as that. Sunbeds put out huge amounts of UVA, although there are some still of the older type that also put out more cancer-forming wavelengths of UVB, which is the sunbed wavelengths. UVA can age the skin but it is also known to be responsible for increasing risks of melanoma. My message is that no sunbed is safe. The real frustration towards us dermatologists is trying to warn people about this. It will prematurely age your skin and will give you a high risk of cancer, and if you've got fair skin and freckles and you're desperately trying to produce a tan, all it does is produce more skin damage and more freckles. You won't get a good tan anyway, but you'll look much older than you need to ten or fifteen years after you've been on your sunbed.
Can I use a sunbed if I'm pregnant?
Your hormone changes during pregnancy make certain parts of your face or body prone to blotchy dark patches called Malasma, and the UVA in the sunscreens will significantly increase your risks of getting that blotchy pigmentation or darkening.