HOUSTON -

If you are headed outside for than than 20 minutes, you will need to take precautions to protect your skin from cancer.

"Skin cancer in Texas is a big problem. It's growing by leaps and bounds," said dermatologist Dr. Brian Ransdell with Kelsey-Seybold, The Woodlands.

Dr. Ransdell sees cases of skin cancer every day. "I've had patients who noticed a new spot and within a month, it's invasive so it's important to act quick do your monthly checks."

Now that summer is in full swing, he says use sunscreen with an SPF 45 or higher and apply a shot glass full 30 minutes before you head out. Reapply at least every 2 hours.

"Using sunscreen is very important, especially under age 18. That's when the cells can be altered and that's when cancer begins early in life," said Dr. Ransdell.

He says most people apply spray-ons incorrectly.

"Spray it on then use your hands to rub it in. People seem to always spray it on like it's cooking spray or spray paint and they seem to miss areas."

Sun-protective clothing and big hats can add extra protection.

Dr. Ransdell says melanoma can develop even from getting sunburned once or twice a year. In men, it is most common on the back. For women, it is the legs.

"So melanoma is hard to find places you don't think you're going to find it," said Dr. Ransdell.

He says those most at risk of skin cancer are people who grew up in the south with more sun exposure, those with fairer skin and any family history of skin cancer, especially melanoma.

For more information, visit the skin cancer foundation at www.skincancer.org.