Sun Damage on Skin

M. D. Anderson Cancer Center
Date: May 2008

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Dr. Susan Chon, assistant professor of dermatology at M. D. Anderson Cancer Center, speaks about the effects of sun exposure during a lecture on skin cancer prevention.

What happens from too much sun exposure? Of course immediately, you see a sunburn and you get that initial redness that day and then as it fades, "you get tan" and that's a response to damage. Your skin is saying I have damage. I need to try to protect myself, so it up-regulates and starts making more of this melanin, this pigment. So that this pigment will actually sit on top of your DNA of your cells and protect it. That's why you get a tan.

The mild reaction as I mentioned and everyone's probably had, it's little red, it's uncomfortable, it's sensitive, but moderate to severe actual reactions are on patients coming in with blistering, you know oozing burns. And they're pretty bad and when they get bad, sometimes they actually have to be, you know treated with oral and systemic medications, and they're just cooling, so you they distract your skin from pain, instead you feel a cooling sensation. If it's pretty bad, we start administering topical corticosteroid creams and then, if it's, you know, if it's really quite diffuse, you want diffuse anti-inflammatories. That way you will take an oral aspirin or ibuprofen. And then of course if it's really bad, you may have to see a physician for basic wound care.

And I mentioned this already, the tanning, it's actually true melanogenesis. Your skin is trying to make this pigment -- this pigment packets to basically cover their DNA and protect them.

Photoaging: This is what we see over time and that's why it's hard to, you know, kind of explain to teenagers and young adults. They don't see it yet. It doesn't happen right away. It takes decades to form and by the time you see it, it's -- it's not too late, but you know it's kind of slowing down the process already. So what do you see? You see fine and deep wrinkles, you see drier skin, you see broken blood vessels, that's telagectasias, sallowness or yellowness of the skin; it's more lax because a lot of the sun damage goes under the skin. It breaks down your collagen and all the fibrous tissue that holds your skin together. And once that it gets "melted down," there's nothing holding up your skin, so it becomes more loose. Yes, you'll get coarser skin. You can get blackheads and things like that.

So this is a classification of the types, basically sun damage or aging that occurs. In type 1 skin in this example here, you see no wrinkles and the patient has, you know nice curvature of her skin. There's no kind of hollows or anything, but in type 2 skin you'll start losing some of the laxity and you can see that she does have, you know, when she smiles, some wrinkles. So wrinkles start developing with motion. You don't see them at rest, so if her features relax, you still won't see the wrinkles. It's just when she smiles now, there's wrinkles around her mouth and her eyes. Type 3 is actually, you're seeing wrinkles at rest. She's not doing anything, but you can see deep wrinkles, a lot of brown pigmentations starting to show up. And in type 4, you can see a lot of laxity of the skin. The skin is actually kind of, almost drooping off of the bone structure underneath, kind of just loose.

One of the most common things, and people get this very early on, teenagers, young adults, it can get bad, is just pigment change. You get what we call lentigines or sun spots, liver spots. And these are just showing you again, there's increased pigment production by your skin to protect itself. The bad news is that sometimes with the right genetics and the right amount of sun exposure, you can get a lentigo maligna, which is basically a melanoma of a freckle.

Melasma is something that happens when you have basically a lot of hormones and sunlight. So often young women who are either pregnant or on birth control pills. It doesn't always just occur on the face. I've had some patients have it on the back of their hands, or their arms, and even some patients who are taking hormone replacement therapy later.

Wrinkling. Again, you lose a lot of this collagen elastic tissue that supports your skin and so you start getting these, kind of folds in the skin.

Broken blood vessels. This is another way of showing you sun damage. And the reason is the sun penetrates again the supportive structure around the blood vessels. So, there's no more support on those blood vessels. They dilate permanently. Also, the constant heat exposure damages the elasticity of the blood vessels too. So there's a lot of broken blood vessels especially on the sun exposed areas of the nose and on the cheeks.

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