Medically Reviewed On: June 23, 2008

SUSAN CINGARI: Hello, I'm Susan Cingari, and welcome to our webcast in Miami.

We all know we should wear sunscreen when spending time outdoors to prevent skin damage and cancer. But there are a lot of sunscreens out there and if you're like most people, you may be confused when faced with the option of choosing them all.

Joining us now to discuss how to pick the right sunscreen are two dermatologists from the University of Miami. Dr. Betty Bellman, to my right, thank you, Dr. Bellman, for being here, and Dr. Barry Resnick to my left.

Let's start with you, Dr, Bellman, first. I go to the store, and I know I'm supposed to wear sunscreen and I'm out there, and I look at all these different products and I go, "Which one is the right one?"

What is SPF first, what do those numbers mean when it comes to sunscreen?

BETTY BELLMAN, MD: SPF is sun protective factor, and that mainly means UVB protection. It comes in all different types of numbers, 2 through 60, and basically what it means is if it takes 20 minutes for a person to get a sunburn, the SPF allows you to spend twice as much time in the sun to get that sunburn. So if it's an SPF 2, you can spend twice as long in the sun before you get sunburned. If it's SPF 15, you can spend 15 times longer in the sun before you get sunburned. That's what an SPF means.

SUSAN CINGARI: Now keeping with that same train of thought, is there a minimum of SPF we should use, say, for the time period, if you're out between 10 and 4, which we know is the worst time. Should you be using a higher SPF? That would seem to make sense to me.

BETTY BELLMAN, MD: All you need is an SPF 15, that is the main number that really the public should look for. The Academy of Dermatology has changed the regulation of the SPF factor to basically include 15 and 30, so 15 is really the number that people should be looking for when they're out in the store looking for sunscreen.

BARRY RESNICK, MD: While it's the minimum, I think that people should know that it's not a license to go out and sit 15 times as long in the sun knowing that you're protected, because people don't usually apply properly, They don't put it on in along enough time before they go out. And then when they go out in the sun, they go and they play in the water, they'll towel down, and you're taking that off of your skin, so you need to reapply it. There's a whole routine on how to do it that will enhance the protection.

And although we're now going to hopefully restrict ourselves between 15 and 30, there are people with skin conditions and skin diseases that are going to require more of a protection. The 60 is what we would call a sunblock. And for people who have those conditions or people who have undergone cosmetic procedures like laser resurfacing, a 60 is really important, especially in the days afterward, so that they protect themselves from overexposure.

SUSAN CINGARI: What about if you've got an unusual skin type? Maybe you've got acne, or maybe you've got a skin condition. Do different skin types require the same SPFs?

BETTY BELLMAN, MD: Many times you can have a sunscreen that has makeup in it, that has physical blocks of zinc oxide or titanium dioxide in it, but a 15 is the minimum that really people should use. If they have at least three active ingredients on the back of the label, that's the minimum number of active ingredients that you want to look for to protect you from the sun. If you go with a 30, that might have three or four active ingredients, including a physical block like titanium or dioxide, or zinc oxide, which is in small particles called micronized; because that's really important because it blocks the rays of the sun off your skin. It actually deflects them off your skin.

SUSAN CINGARI: I was going to ask what those three active ingredients might be.

BARRY RESNICK, MD: Well, they can be things like octyl-methoxycinnamate, they can be benzophenone, they can be Parsolâ 1789. And I think it's important, let's take it one step back and tell you what a physical and a chemical sunscreen is.

Physical sunscreens, like Betty said, are actually reflective things, like titanium dioxide and zinc oxide. The original sunscreen, that white paste that lifeguards used to use, was zinc oxide. And it is the best, it's a block. Nothing gets through that, but certainly it's cosmetically unattractive.

So then they started to color them. They made things in purples and bright greens. And kids liked to use them, but it's again, not something you're going to be smearing on your body every day. That's a physical sunblock.

A chemical sunblock, or a chemical sunscreen, is something that's going to absorb the wavelength of light and keep it from your skin. So you've got on the one hand reflective and you've got on the other hand absorptive.

And she's right, we need to keep a minimum of three things so that you get protection from both ultraviolet B, which is the most damaging of the sun rays, and the thing that provides the most redness in your skin from sunburn; as well as UVA, which is a more insidious form. It takes a long time to get sunburn from UVA, but it gives you a lot more sun damage.

SUSAN CINGARI: Dr. Bellman, what about sunscreens for babies? What kind should be applying on little, little, teeny babies?

BETTY BELLMAN, MD: Recently, the American Academy of Dermatology said it was okay to apply chemical-free sunscreen to infants under the age of six months, meaning no chemical, just the active ingredient should be titanium dioxide or micronized zinc oxide particles. Of course, ten to four, you don't want to go out in the sun with a small infant under the age of six months, and to apply it to the areas that are going to be sun exposed is okay, as long as it's chemical free.

BARRY RESNICK, MD: And as for kids, I think that parents are missing a great opportunity to instill in their kids the habit of using sunscreen every day. You can use an SPF 15, you can use whatever form you can find that the kids are going to want to use. If they like the bottle that says it's for kids, and it's got little animals on it, or if it's a glitter sunscreen or if it's a spray that they like to spray on each other, or a foam that they can squeeze out of a bottle. The best time is to do it before they go to school, you should do it before you dress them so that they get all of the areas covered, and it becomes a habit form, and then they're going to be reminding you. "Hey, dad or mom, I have to put my sunscreen on."

BETTY BELLMAN, MD: We hope.

BARRY RESNICK, MD: We hope.

SUSAN CINGARI: What about young people? I know they like the glitters, the scents, the foams. Do those work for them? The young teens like to put on kind of the fun stuff, I call it.

BETTY BELLMAN, MD: Yes, they enjoy it because it's very popular, it's very trendy to use these glitter, gold and silver and purple sunscreens. And they can make it a fun hobby when they go to the beach, and compare which brand they have or which brand the other one has, and it's very popular amongst teenagers.

But a lot of my patients tell me that when they use their sunscreen, they feel like they're 100% protected from the sun, like nothing bad can happen when they use these sunscreens. But they're not 100% protected.

BARRY RESNICK, MD: That's definitely a fallacy. And when people use a sunscreen, they've got to keep in mind the fact that it doesn't eliminate the need to wear a hat, to stay out of the peak hours of sun, where you've got from 10 to 4, and to reapply it.

When you've got glitter sunscreens., when you've got sunscreens with color in them, when you've got sunscreens that smell good or spray on or are in a pad form or in a gel form. Anything that we can do as dermatologists to enhance someone's ability to use it, someone's compliance, is going to protect. And no matter whether you live in Miami or you live in Minneapolis or you live in the tundra. You're going to get sun damage and sunburn.

And a lot of times, people who live up North don't think they need sunscreens because, oh heck, they don't like in Miami.

SUSAN CINGARI: I oftentimes see these different kinds of sunscreen that are alcohol based or water based. What are those and who should be using those types?

BARRY RESNICK, MD: Alcohols and waters and oils, they're all referring to the vehicle. The sunscreen itself is a powder, and you pour the powder into a vehicle. The vehicle can be a liquid, it can be a lotion, it can be a gel, it can be a water based gel or an alcohol based gel; you can put it on a pad. And it's just the vehicle, it's the truck by which you get it to your skin. Alcohol is a dryer, and it rubs in more quickly and doesn't leave as much of a residue, the same thing with a water based lotion.

The thicker and more tenacious the vehicle, the longer you're going to have the protection. One of the things we'll talk about is waterproof or water resistant. It's real interesting how they determine that, but the whole point here is that you really shouldn't assume that anything is waterproof or water resistant, you've got reapply.

SUSAN CINGARI: You just mentioned a few minutes ago that people up North don't think they need to wear a sunscreen. That brings me to my next question, about climate.

How does the climate affect what product you should by? Suppose you are skiing. Do you need a sunscreen when you ski and what kind should you be using?

BETTY BELLMAN, MD: Absolutely. The rays of the sun reflect on the snow, and it's very, very misleading. You think, "OH, I'm up North, I'm skiing, I don't need any sunscreen," but you can get burned very easily because you're at a higher altitude. And every one thousand feet that you go up, the rays of the UVB intensify by 10%, so you're getting even more UV damage.

BARRY RESNICK, MD: Have you ever gotten owl eyes?

BETTY BELLMAN, MD: No.

BARRY RESNICK, MD: No, when you go out and you wear sunglasses?

SUSAN CINGARI: I haven't, thank God!

BARRY RESNICK, MD: People go out there, they wear their sunglasses with the little shields on the sides, and then you take them off, and you've got own eyes. You see that every day on the slopes when you're watching the Olympics. No one wears sunscreen when they're out skiing. It's as important as when you're at the beach.

BETTY BELLMAN, MD: They need to, definitely.

SUSAN CINGARI: But what about you're out there, you're the weekend athlete. Maybe you're not skiing, maybe you're bicycling. Do you use the same kind of sunscreen that you use at the beach? Or maybe you're playing tennis? What about different activity levels and the need for sunscreen when you're out doing athletics as opposed to just casually strolling down shopping?

BETTY BELLMAN, MD: There's a difference between the type of sunscreen that I tell my patients to use on their face versus their body. People who break out a lot, who get a lot of acne, might wear something that's oil free or light on t heir face, where they'll wear something a little bit more sweat-proof or rub-proof on their body, so that they could go biking for two hours, sweat in the sun, and not worry that for those two hours they'll have to reapply the sunscreen, it will last for approximately that long a period of time.

BARRY RESNICK, MD: You really want a sunscreen that has a vehicle that's going to hold onto your skin when you're going to be very active, when you're playing volleyball on the beach or when you're mountain biking through the Everglades. And you want it to stay on for as long as you're going to be exposed. And you really again have to remember, you've got to reapply it when you towel down.

SUSAN CINGARI: Quickly, we have time for just one more question.

If you're on medication, maybe you're on an antibiotic, should you use a sunscreen? Because sometimes I know that it can make you more photosensitive.

BARRY RESNICK, MD: Absolutely.

BETTY BELLMAN, MD: Definitely. It depends on the antibiotic, of course. Some of them are photosensitizing, they can make you more sensitive to the sun, others are not. You can always ask your doctor if you're not sure, but I think wearing sunscreen on a daily basis when you're driving around or walking around. You're getting photo damage, you're getting sunrays that can make you get wrinkles and skin cancer. So you really need to wear the sunscreen in your moisturizer on a daily basis.

BARRY RESNICK, MD: If you make it a habit you're going to do it every day. And when you combine a moisturizer in a sunscreen for face or for body, you're going to be protected casually every day that you put it on. And the more you protect, the better you'll look.

SUSAN CINGARI: Dr. Barry Resnick, thank you so much for your time; Dr. Betty Bellman, thank you. I think we've cleared up a lot of misconceptions about how to pick the right sunscreen.

I'm Susan Cingari. Thank you for joining us for this webcast from Miami.