It's summertime, it's hot, and the sun is so bright and inviting; but there is a great danger - the sun can harm you. Janet Fairley, MD, UI Hospitals and Clinics dermatologist, head of the department and recently appointed to the John S. Strauss Chair in Dermatology, talks about UV rays.

People associate a dark sun tan as looking " healthy. " Ironically enough, there is a phrase--killer tan--that literally can be the case. Is there such a thing as a healthy suntan?

The reality is no. Suntans are a response to injury of the skin, so every time you see a tan developing on your skin, it's doing that because your skin has been damaged. You're absolutely correct, over the long haul sometimes, with that leading to skin cancer, so it does become the killer tan.

What do ultraviolet sunlight rays do long-term to our skin?

The ultraviolet light has several effects on the skin. First of all, it, over the long haul, causes degeneration of components of your skin called collagen and elastin. They're part of what gives skin its flexibility and its youthful look, so damage to those will lead to what we see as aging of the skin with wrinkling. The ultraviolet light also stimulates the cells in the skin that give it its color, the melanocytes, that's part of why you get a tan, but also over the long-term you start to see really irregular freckling and color change in the skin. That's also part of the damage to the skin that we perceive as aging of the skin.

Does repeated sunburning over a lifetime increase the chances of developing skin cancer?

Both sunburning and chronic sun exposure probably increase the risk of skin cancer. With some types, such as melanoma, it seems like acute burning may be almost more problematic than chronic sun exposure. But for other more common types of skin cancer, the chronic long-term exposure to sun is probably a greater problem.

Are certain people or certain skin types more likely to burn and, therefore, more likely to develop skin cancer?

Absolutely. Folks with fairer skin, red hair, freckles, that burn very easily are going to be the folks that most likely get into trouble. Folks who tan very easily, the tan, even though it's a response to injury, also provides some protection for those folks. So if you tan very easily, you're probably a little less likely to develop skin cancer.

Aside from avoiding the sun entirely, what are the best ways to prevent sun damage to our skin?

There are certainly several things you can do. Number one is to avoid a lot of outside activities in the mid-portion of the day. Usually 10 a.m. to 2 p.m. are the most intense times for sun exposure and the best times to sit back, relax, do something outside of the sun. If you're going to be outside, then proper use of sunscreens is probably the number one thing that people think about as far as protecting their skin. And the other thing is sun protective clothing. Some clothing will provide significant protection from sun exposure.

What level of SPF and how often should sunscreen be applied when outdoors?

Sunscreens need to be applied, probably at a minimum of every two hours, when you're outdoors. And the other thing to note is it's best to apply your sunscreen 15 to 20 minutes before you go out that first time. It takes a little time for the sunscreen to be absorbed into the skin, so first application 20 to 30 minutes before you go out; then reapply it every two to four hours when you're outside; every time after you go in swimming; if you're sweating a lot, it's going to wash off some of that sunscreen, so you may need to even apply it more frequently.

I don't think anybody should be going less than 15 SPF if you really want sun protection. If you have very sensitive skin, if you have a family history or personal history of skin cancer, then you may want to go up more to the level of 30.

Are UV rays something we should only be worried about in the heat of the summer, or are UV rays just as harmful in the winter sun?

In a place like the Midwest, the intensity of the ultraviolet radiation does decline in the winter, but I generally recommend, particularly for folks who want to protect against skin cancer or aging of their skin, use of sunscreen year-round. The other thing is that if you're somebody who does a lot of outdoor sports, if you're a skier, then you get reflection of the UV off of the snow and up onto the skin, and in some areas, if you see folks who go out to Colorado skiing or something, they'll come back with a nice healthy - nice un healthy - sunburn, even in the middle of January.

An ounce of prevention is absolutely worth a pound of cure.

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