TERRY GROSS, host:
This is FRESH AIR. I'm Terry Gross. It's summer sun season, although you wouldn't know it in Philadelphia, where I live, because it's been cloudy and rainy nearly every day.
That summer suntan that we used to think gave us a healthy glow we now know is probably damaging our skin and maybe even leading us a step closer to skin cancer, but those sunscreens with the SPF numbers, do you know what those numbers mean?
Here to help us understand the sun's effect on our skin and how to best protect ourselves, without becoming shut-ins, is dermatologist Dr. Darrell Rigel. He specializes in skin cancer, sun damage and aging problems of the skin. He's former president of the American Academy of Dermatology and former director of the American Board of Dermatology. Dr. Rigel is also a clinical professor of dermatology at NYU Medical Center.
GROSS: Dr. Rigel, welcome to FRESH AIR. So what does the SPF measure?
Dr. DARRELL RIGEL (Dermatologist): There are three kinds of ultraviolet radiation: A, B and C. UVC is blocked by the ozone layers. We see very little of it on the Earth's surface, although we are seeing a little more with ozone depletion.
That leaves us A and B. A is the kind of light you see at the black light era, you know, light at the disco or something. That's ultraviolet A. It's the nearest to violet. And B are the rays you really can't see, but they're more involved with burning of the skin.
SPF just measures the amount of UVB that it's blocking, the UVB protection level is what it is, and it's really a ratio of the amount of time you can stay out in the sun with the sunscreen versus without the sunscreen and not be sunburned.
So let's say, if you had typical skin where you burned in 20 minutes, if you had an SPF 10 on, it would take you 10 times that, or 200 minutes of exposure, to burn. That's a very simplistic explanation, but that's the idea behind SPF.
GROSS: So the SPF numbers seem to be getting higher and higher. So if you get into the real high numbers, like 100 or something, are you twice as protected as you are if you were using an SPF of 50?
Dr. RIGEL: Well, you know, that's one of those questions the debate goes back and forth on. It's almost the question: Is the glass half-full or half-empty, or in this case, is it 98 percent full or two percent empty?
An SPF 50, in theory, if it's used correctly, and that's a whole 'nother issue, would block 98 percent of the sun's UVB rays. So that means only two percent would get through. An SPF 100 would block 99 percent of the rays.
So you can say, well, there's not a lot of difference between 98 and 99 percent, but the reason you could argue it the other way is it's twice as good, is that only one percent's getting through instead of two percent. So only half the rays are getting through, and that's really - it's a bit of semantics, in a sense, but that's why as you get to the higher SPFs, the additional protection is not that much, but there are reasons to have higher SPFs.
GROSS: Would you use a higher SPF? Do you think it matters?
Dr. RIGEL: Well, I personally do. I actually use either the 70 or the 85, and I'll give you my reasons why. When sunscreen is tested, it's tested in a way that's really not used in the real world, and it goes back to the 1970s, when sunscreens first began to be tested, where they used two milligrams per square centimeter of body surface.
That doesn't sound like a lot, but if - no matter what you look like, if you were to put that on, everybody would look like Casper the Friendly Ghost or the Michelin Man or something. You'd be white as a sheet. So realistically, nobody uses sunscreen the way it's rated, and that's actually unfortunate. The FDA is looking at different ways to re-label sunscreen. One of the things they should look at is how they measure SPFs.
But all that aside, if you under-apply sunscreen, and most studies show that people only apply about 20 to 50 percent of the rated amount, you're getting a lot less coverage, a lot less protection, rather, than you would see with the actual SPF on the label. So the higher SPFs are much more forgiving, and that's really the argument for them.
People are going to skimp and under-apply anyway, but you're getting - maybe if you use a 75 or an 85 or a 100, you're getting the protection of a 15 or a 30, even though you're under-applying.
GROSS: So can you give us a sense of how much we're supposed to be putting on? Like how greasy should we really be?
Dr. RIGEL: Well you know, that's a great point, and typically to cover your whole body, if you were covering your whole body at the beach, you'd use one ounce. Now, one ounce is the amount of - I hate to use this analogy as a physician, but the amount of a shot glass. Everybody can relate to that size.
Most people under-apply sunscreen, and I always love the question. Typically sunscreens come in three-ounce tubes or bottles because you can take them on the - in your carry-on bag in the airlines now, right, because they have to be three ounces or smaller.
Dr. RIGEL: So theoretically, one tube should last for three complete body applications, right? And I'll get patients who will come in and say, you know, I've this tube of sunscreen I've been using for three years, is it still good?
Well, theoretically, if they were at the beach, it should have lasted for three applications. So clearly they're under-applying, but that's typically how you go through this exercise.
GROSS: Say you're just, like, putting some on your nose or something like - how thick a layer should it be? I mean, you can't use the shot-glass analogy there because you're not covering your whole body.
Dr. RIGEL: Typically for the face, that should be a heaping teaspoon or a flat tablespoon will cover your face. That's typically what you're looking for, face and neck, to do that.
And you know, the trick what I do, is you don't want to put it all on one side and then start rubbing the other side; it becomes very uneven. So I typically take the right amount, and then I dab it around my face and my neck, and then I rub it in. So I sort of spread it a little more evenly.
If you do that, you avoid the problem of having too much when you first put it on, and it's too gloppy, and then too little on the areas you're finishing up with. And sunscreens used to be called sunscreens and sunblocks, two different things. Now they're called organic and inorganic for the screens and the blocks.
The organic ones are the ones we talk about, typically the sunscreens that absorb the sun's radiation, and the inorganics, or the old sunblocks, were the ones that reflected, like zinc oxide or titanium dioxide. Those you can often see on the skin when they're there, but the sunscreens, typically, rubbed in enough, you don't have to see them and they're working.
GROSS: After you've applied your shot-glass-worth of sunscreen, how long will it last?
Dr. RIGEL: It starts to degrade at about an hour. Many of the sunscreens by two hours are pretty much gone, with the exception of some of the newer formulations that will last four hours or longer.
The - you know, four hours for a sunscreen is pretty good because if you went out, let's say you were in daylight saving time in the summer, that would cover you from 11:00 till 3:00, which will be most of the time when the rays are strongest, and you might get by with one application.
But if you're in the water or you're sweating or you have clothes rubbing on you in the areas where you are, something that is mechanically taking off some of the sunscreen, you probably should re-apply every two to three hours.
GROSS: Okay, so the sunscreens protect you against the UVB rays, but there's the UVA rays. Are they damaging too, and are we getting any protection against them?
Dr. RIGEL: Well, we are. I mean, that's really where a lot of the current controversy exists. As I mentioned, SPF on the sunscreen bottle currently just measures UVB protection, and if we were talking 15 years ago, what we would have said is that UVB is much more important than UVA, and in fact to get at SPF 15 or higher, you're putting enough sun-screening agents in the sunscreens such that you're getting some good UVA protection.
But that all changed about a decade ago, when a really nice study was done in Canada, looking at six SPF 30 or higher sunscreens and measuring their UVA protection, and it turned out their UVA protection was all over the map.
So it made us really rethink how we measure UVA protection, and in parallel to this we started learning that UVA was more - we talked about it in the past, they'd be the aging rays and things that cause the aging in their skin, and they do, but they also lead to skin cancer.
So the real issue now is you have no way easily of knowing the best sunscreen for UVA protection, and that's what's before the FDA right now, and believe it or not, they have been working on this since 1978, 31 years, going back and forth, and we're hoping finally that they will come to some closure on this in the next couple of months.
GROSS: So meanwhile, when you're putting on sunscreen, and it says waterproof, it makes you think, well, you could go swimming, and you don't need to re-apply it, do you need to re-apply it?
Dr. RIGEL: You do. It's interesting: The whole term of waterproof in the new FDA proposals will be removed, and they'll be able to call things water-resistant and very water-resistant as opposed to what they call things now, water-resistant and waterproof.
That's a whole 'nother story, but it goes back to the 1970s when they were first testing sunscreens, and they were tested in a lab, actually in Philadelphia, in the University of Pennsylvania, and in that lab they had a 40-minute timer. So what they did is they put sunscreen on people, they put them in the pool for one cycle of 40 minutes, and they came out and tested them, and if the sunscreen still worked after 40 minutes in the pool, it was called water-resistant, and if went through a second cycle, another 40 minutes or 80 minutes total, it was called waterproof.
So the FDA adopted these things, and for, again, the bizarre reason of why 80 minutes - it just happened to be twice the 40-minute timer, and that's actually still used when they do the tests on sunscreens. But since there's no sunscreen that's truly waterproof, the terminology will be water-resistant and very water-resistant to do that.
What's interesting in the last several years, the sunscreen manufacturers have come up with formulations that are much more resistant to breaking down.
I mean, the way sunscreens work is they, as I said, they absorb the ultraviolet radiation. Actually, what they actually do is they turn the ultraviolet radiation into a very soft red light, which you can't see in the daytime because it's too bright, but it converts the UV to red, which is harmless, and that's how it offloads the energy. But after a while, the sunscreen will break down from doing that.
The newer sunscreen formulations do last longer than two hours. We've done studies which show that pretty much every two hours you have to re-apply, but with some of the formulations, they do last four hours or longer and still give you good protection.
GROSS: Well, if you're just joining us, my guest is Dr. Darrell Rigel, and he's a dermatologist who specializes in skin damage caused by sun and in skin cancer and aging problems of the skin, and he's a clinical professor of dermatology at NYU, past president of the American Academy of Dermatology. Let's take a short break here, and then we'll talk more about skin issues and the sun. This is FRESH AIR.
(Soundbite of music)
GROSS: If you're just joining us, my guest is dermatologist Dr. Darrell Rigel. We're talking about skin and skin damage from the sun and how to prevent it. He's a clinical professor of dermatology at NYU, past president of the American Academy of Dermatology. He specializes in skin cancer, sun damage and aging problems of the skin.
Now, I'm from the generation where a lot of people used, when they were young, sun reflectors, which is basically a piece of cardboard with something that looks like tinfoil on it to reflect the rays of the sun onto your face so that you get a quicker, more intense sunburn or more - more, hopefully, suntan. How much did those of us who used these things damage ourselves?
Dr. RIGEL: Well, pretty big time. You know...
GROSS: Thank you.
Dr. RIGEL: Make you feel really good, right?
Dr. RIGEL: You know, the idea behind that was you just got extra rays hitting you. So think if you had direct rays, and you multiplied it by two or three because you get the extra reflected ones, you're going to get more intense ultraviolet radiation.
I mean, these were basically the precursors to the tanning beds, if you think about it, because tanning beds have UV intensity of 10 to 15 times that of normal sunlight, and you obviously tan faster in a tanning bed. That's why people go there, but you also get your damage faster.
GROSS: So are you seeing a lot of patients who used sun reflectors and now have various forms of skin damage or skin cancers?
Dr. RIGEL: Absolutely, and typically what you see is you get the person who said, well, I protected the rest of my body, but I wanted my face to have color, so I used a reflector, or I used a sunlamp, or I used - years ago whatever the things - and now they're in their 50s or 60s or whatever - because those were big in the 1950s and 1960s - and you see the extreme damage they have on the face, and they have pre-cancers. Well, they have aging, they have pre-cancers, and they often have skin cancers.
GROSS: A lot of people are getting diagnosed with basal cell carcinomas and being told that they don't really have to worry a lot about it if it's diagnosed soon, and it's superficial. Would you explain what they are and how much we need to worry about them?
Dr. RIGEL: Sure. There are three basic kinds of skin cancer, and they have to do with which is the cell that turns cancerous. The most frequent kind that we see is basal cell carcinoma, and that's the basal cell. It's the lowest cell in the epidermis, and it becomes cancerous from ultraviolet exposure.
There will be over one million newly diagnosed cases of basal cell carcinoma this year in the United States alone. So it's the most common cancer, and in fact it's almost as much as the sum of all other cancers combined.
So it's very common. About one in six Americans or so will get a basal cell sometime during their lifetime. They grow very slowly. They rarely, very rarely, metastasize. Usually it'll be if somebody has other problems with their immune system, such as, you know, if they're immuno-suppressed for transplants.
If you do catch them early, not a big deal. Even though they don't metastasize, though, they can become locally destructive, and one third of all basal cells appear on the nose. So you can imagine it starts to eat away at your nose, you have some issues in terms of your appearance, as well as potentially it can get in deeper structures, get infected.
So you can't let them go. You've got to treat them, but once you treat them, they're pretty much treated, and there are a variety of ways to do that.
Once you've had one basal cell, your chance of getting a second basal cell sometime in your lifetime is about 50-50.
GROSS: In the same place, or in another place?
Dr. RIGEL: Well, anywhere, anywhere on the body, because you've proven, you've proven you have the sensitivity to grow them, and you've proven you've been successful at growing them. And it's probably from the same sun you got 10 or 20 or 30 years or so before, it's just they're like dandelions. They'll pop out in different spots. Not the first one spreading but another one popping up.
GROSS: So how do you recognize that you have one and therefore go to see the doctor about it?
Dr. RIGEL: The way you look for it on the skin, in terms of basal cells, it's typically a spot that's just not healing. And the story - I had a spot - remember, one third of them on the nose, so a typical story was it was on my nose, I thought it was a pimple, but it never quite healed up. It crusted a little bit, it bled, but it semi-healed and it came back. And again, they grow very slowly, so often it's several months before somebody comes to me for having these diagnosed, but that's, I guess, your typical story.
So if something is growing, bleeding, crusting or changing on your skin, see your dermatologist.
GROSS: And same kind of thing on your ear, or - do you get a lot on your ear?
Dr. RIGEL: You can, and it's sort of interesting. Men get skin cancers on the ear about six times more frequently than women, and that's primarily due to hairstyles, right?
GROSS: Oh, sure.
Dr. RIGEL: So that's universal across all countries that you see that. On the ear, often what you'll get is a squamous cell carcinoma, which again, that's the squamous cell, the intermediate kind, that turns cancerous.
There are about a quarter of a million cases of squamous cell carcinoma each year in the United States, and again, if you see a red, rough, scaly spot on your ear, which you also could see on the face at other times too, or the backs of the hands are a typical site for squamous cell, that's typically what you'd see and obviously have it looked it.
The squamous cell carcinoma, again, is typically, as with the basal cell, with people who have had chronic sun exposure. So they are people who spend a lot of time outdoors, haven't protected themselves. It's not from one sunburn, but it's a lot of outdoor exposure for those two types of skin cancer.
GROSS: And with melanoma, the most deadly of them, if it's not caught early, is melanoma also caused by the sun, among other things?
Dr. RIGEL: Well, absolutely. The vast majority of melanomas can be traced back to sun exposure. The difference with melanoma it appears is not the chronic sun exposure as much as the sunburn that does you in, and you can look at a whole bunch of studies with melanoma that in terms of intense ultraviolet radiation does you in, sunburns, blistering sunburns. All those things increase your risk. The more of those you've had over life, the greater your risk, tanning beds, where the UV intensity is so much greater than it is in normal sunlight.
And melanoma is really - it's again, a cancer of the melanocytes, the pigment cells. So in most melanomas you see a brown or a brownish-black or almost a black spot that's growing early on, and typically in early melanoma what you see is a brown spot that's got several different shades of brown.
Instead of being nice and round or oval, it almost looks like it has little pods sticking out, like a spider almost or something, or a little lobster or something, but the easiest way to recognize early melanoma is A, B, C, D, E.
A is asymmetry. Early melanoma typically is not symmetric because one part of it starts to grow a little different than the other part of it. So you get that asymmetry.
B is border. On normal moles, typically they have a very clear-cut border. You can see where the mole stops and the skin starts. With early melanoma, that border is either ragged, irregular or indistinct.
C is color. Most run-of-the-mill moles, they can be light, they can be dark, but they're pretty uniform in color, while melanoma will have multiple shades of brown or some blacks, even some blues sometimes.
And then D is the diameter of being six millimeters or a quarter of an inch or the size of a pencil eraser. So if you have the asymmetry, irregular border and uneven color and diameter greater than a pencil eraser, and now we've added E to that, evolving, so it's changing on top of that, those are suspicious signs to see your dermatologist and get the early melanoma removed.
GROSS: And if you get it removed early, you're probably in the clear?
Dr. RIGEL: Basically, yeah. Melanoma, the variable that best measures how you're going to do is how thick the melanoma is - in other words, how far it goes down vertically.
A melanoma that's only gone down one millimeter or less, that's a 25th of an inch, basically 95-plus percent of the people who have that will survive and do well. A melanoma that's gone down three millimeters, or an eighth of an inch - it's not much difference between a 25th of an inch - the survival is only 50-50. If you go down to four millimeters, which is roughly a sixth of an inch, then the survival drops down to about 30 percent.
So those couple of millimeters' difference is the difference between life and death in melanoma, and that's why it has to be detected early. A melanoma the size of a dime on your skin, which is not that big, has a 50 percent chance of having already spread, and once melanoma spreads, basically nothing works.
So that's why it's such a lethal cancer, that it spreads rather early in its course.
GROSS: Is it worse for your skin to sunburn it when you're a child than it is when you're an adult?
Dr. RIGEL: Well, it's always bad to sunburn your skin. Let's start with that premise first. And you know, by the fact that your skin burns is a sign you've had ultraviolet exposure and it's damaged you. And actually there's data to show that people who have even one sunburn, if you can - they do some studies where they'll take people's rear ends that don't normally see the sun, and they'll give them ultraviolet radiation exposure for just one light sunburn, and you can see DNA damage and genetic damage in the skin for four to five days just from one exposure in a place that's never been exposed.
So you know, that is a major issue associated with - but there are papers that were written 20 years ago that suggest that the sunburns you had prior to the age of 18 were worse than the sunburns you had afterwards in terms of risk, but it turns out that's not true.
There have been several studies come out in the last, well, three or four years that show basically whenever you get the sunburn, it's harmful to you in terms of subsequent skin cancer risk.
GROSS: Dr. Darrell Rigel is a clinical professor of dermatology at NYU Medical Center and former president of the American Academy of Dermatology. Coming up, a new biography of Donald Rumsfeld. We'll talk with the author, former Washington Post Pentagon correspondent Bradley Graham. This is FRESH AIR.
(Soundbite of music)
GROSS: This is FRESH AIR. I'm Terry Gross.
Let's get back to our interview about how to protect yourself from the summer sun. My guest is dermatologist, Dr. Darrell Rigel. He specializes in sun damage and skin cancer. He's former president of the American Academy of Dermatology and is a clinical professor of dermatology at NYU Medical Center.
Has the sun gotten more dangerous because of the depleting ozone layer?
Dr. DARRELL RIGEL (Dermatologist): Well that's another controversial point. I'm one of those who believe that it has. Again, if you look at the data on melanoma rates in areas where there's clearly been some ozone depletion - so for example, in the southern part of Chile, which is an area that normally you wouldn't expect to have too much skin cancer, but over the last 15 years - as they map, each year, the ozone hole. They get their ozone hole in early spring, which for them is October, and you see sort of a peak each year going higher and higher, and higher for skin cancer rate. And certainly, in Southern Australia and Tasmania and that area in Southern New Zealand, in fact, you do see some rates higher than you'd expect and increases more rapidly than you see elsewhere in the world. So I think that is contributing, but it's really not the only factor and probably not the major factor, certainly in the U.S. at this point.
GROSS: Then what is?
Dr. RIGEL: Well, when you look at the data in the U.S., I think the one measurable factor is the use of tanning beds. And what's interesting is if you look at the data for both man and for women by age and compare the data from the late 1980s to the late 1990s, almost all the increase of melanoma in men and in women where people, 45 and older, and again it was expressing the damage that they did 10 or 20 or 30 years earlier. But the young people, the rates were pretty steady and you're still seeing that same trend in young men. But in women you're starting to see a marked increase in women in both melanoma, in their 20s, 30s, and into the early 40s which you don't see in men. And the one factor that is different between men and women - young women - is the use of tanning beds.
And the tanning industry is very large. There are about oh, a quarter of a million tanning beds in the United States. At least the tanning industry's own data is that about a million Americans go to a tanning bed every day. I mean that's phenomenal number when you think about it. But that has to add up over time and the tanning industry really started in the U.S. It's been 20 years or so. Probably the first tanning bed in the U.S. was about 30 years ago, but really it was in the '90s when it started to ramp up a little bit. So we're just beginning to see the results of the tanning exposure from tanning beds as again, with that latency of 10 to 20 years, we're beginning to see the effects of it. But there are now studies coming out showing if you used a tanning bed, your risk of melanoma is greater, your average age that you get your melanoma is younger, the risk of getting a second melanoma is greater, you tend to get melanomas in areas where the sun might not normally shine but does shine when you're in a tanning bed. And I could go on and on with these studies. So there's clearly an association. I call the tanning beds, actually tanning coffins. I think that's a better description for them. But the reality is that it's not a good thing to do and it's very analogous to cigarette smoking in the sense that it always pays to stop.
GROSS: Are fair-skinned people - well I know that fair-skinned people are more prone to sunburn, but does that mean they're also more prone to skin cancers? And conversely, are dark-skinned white people and people of color less prone to skin cancers if they've been in the sun?
Dr. RIGEL: Well that's a great question and it's a very important one for a number of reasons. First of all, in general, the fairer-skinned you are the more easily you sunburn, the less easily you tan, the greater the risk of getting skin cancer. However, even the darkest-skinned individual's at risk. They just have a lower risk than the fair-skinned individual. Roughly the data on melanoma is that the risk of a Hispanic American getting melanoma is about one-sixth that of a Caucasian, and of an African-American it's about 125th that of a Caucasian. But note that it's not zero. What is interesting in people of color is that they typically will get their melanomas in a little different distribution. So often they get them on the palms and soles and not get them as much in other areas. They can, but that's typically where you see them. And why this is interesting, the incidence or the risks of getting melanoma on the palms and soles is the same across all races, whether you're Oriental, Hispanic, African-American descent or Caucasian, your risk is about the same for that.
Of interest though, is that certainly the Caucasian, you're likely to get melanoma in other places, but if you just looked at melanoma of the palms and the soles the incidents is about the same across all races. And this has led scientists, especially Dr. Boris Bastian, who is a dermatologist researcher at the University of California in San Francisco, to hypothesize that there may be more than on kind of melanoma, and he has some genetic studies that he's doing to support that. So we may find that there's one kind of melanoma that's - you see more often that's more sun-dependent and there's another kind that may be due to more genetic predisposition. We're only scratching the surface of this research, but in fact, it's interesting and it may play out quite positively in the future.
GROSS: Now, you know, we've been talking about skin problems including skin cancers that are caused by exposure to the sun. One of the things that you specialize in is the aging skin. So while we're on the subject of aging skin, what do you think of anti-wrinkle creams?
Dr. RIGEL: The reason your skin wrinkles is because the tissue that supports the skin, what we call the connective tissues, weakens over time. And there're a bunch of things that can weaken it, sun exposure is one. If you take the skin and let's say - I'm not advocating doing this, if you did a biopsy of the skin of a baby's rear end, something that's never seen the sun, and you use special stains on that biopsy to see the - what we call the elastin tissue or the fibrous tissue underneath the skin - the supporting tissue, it would look like almost like a deck of cards that you cut in half and half shuffle and half pushed together so you'd have a whole bunch of interleaved parallel fibers that were perfectly lined up.
If you took the same type of biopsy, let's say on a 50-year-old who, on their forearms and had a lot of sun over the years, it would look like a ball of spaghetti because all the fibers would be disoriented and pulling and awry. And that's really one of the reasons why your skin wrinkles, why it ages, why it loses its tone, all those things, what you see. So you know in a sense that's probably the biggest issue you have, and these anti-wrinkle creams are at least allegedly designed to try to give you back some elasticity to your skin. It's very hard to do it and it's not even with, you know, the Vitamin A derivatives, Retin-A and the other retinoids, which are Vitamin A-like substances, it helps a little bit. You know, if you have fine lines and wrinkles with the cream-wise, maybe you get a five percent improvement or a 10 percent improvement. It's not going to work for deep lines really at all. It might work for those little fine lines around your eyes and help a little bit for that, but once you've got the deep lines, no cream is really going to work very effectively.
GROSS: Well Dr. Rigel, thanks so much for talking with us.
Dr. RIGEL: It's been my pleasure to be here.
GROSS: And have a good summer.
Dr. RIGEL: You too.
GROSS: Thank you.
GROSS: Dr. Darrell Rigel is a clinical professor of dermatology at NYU Medical Center and former president of the American Academy of Dermatology.
Coming up, a new biography of Donald Rumsfeld. We'll talk with the author, former Washington Post Pentagon correspondent, Bradley Graham.
This is FRESH AIR.
NPR transcripts are created on a rush deadline by a contractor for NPR, and accuracy and availability may vary. This text may not be in its final form and may be updated or revised in the future. Please be aware that the authoritative record of NPR’s programming is the audio.