Denver is one the smartest cities when it comes to preventing and detecting skin cancer, according to a survey by the American Academy of Dermatology.

Good thing because the city receives roughly 25 percent more ultraviolet (UV) light than those closer to sea level. “Our UV exposure in Colorado can easily double our risk for skin cancer,” says Nicole Annest, MD, board-certified dermatology surgeon with Kaiser Permanente Colorado.

Below Dr. Annest shares ways to prevent and detect sun damage and skin cancer, which is the most common form of cancer in the United States. But first, a lesson on what you’re fighting against.

UV light and your skin

UV radiation’s short wavelengths, known as UVB rays, stimulate the body to produce pigmentation known as melanin. Although this may create a nice suntan, it’s really the body’s attempt to protect itself from further damage.

Long wavelengths, or UVA rays, penetrate the deeper layers of the skin and damage connective tissue and blood vessels. Both types of UV radiation not only increase the risk of skin cancer, but can also cause premature aging and suppress the body’s immune system.

“UV rays damage the structure of the skin, which can cause sun spots, sagging skin, and wrinkles,” says Dr. Annest, who specializes in Mohs micrographic surgery for skin cancer. “UV rays also damage the cells of the skin. That damage can accumulate over time and lead to skin cancer.”

The three most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma and melanoma. Skin cancer warning signs can include a new growth or mole, a change in a growth or mole, a sore that does not heal, or irritation of the skin.

Prevent and detect sun damage

So what can you do about it?

Recognize the signs and symptoms. Examine your skin once per month for new skin growths or changes in existing moles, freckles, or bumps. Look for any abnormal skin growth or any change in the color, shape, size, or appearance of a skin growth. Check for any area of injured skin (lesion) that does not heal.

Avoid peak sun hours. Limit outdoor activities between 10 a.m. and 4 p.m. when the sun is the strongest – even when it’s cloudy.

Check your meds. Some prescription medications and over-the-counter drugs, including antibiotics; certain cholesterol, high blood pressure, and diabetes medications; and immune suppressing medications can increase your sensitivity to the sun. Take extra precaution or avoid the sun if you take these.

Apply (and reapply) sunscreen. “Sunscreen needs to be reapplied about every two hours for it to maintain the sun protection factor (SPF) listed on the bottle,” says Dr. Annest.

Call your physician. If you notice changes to your skin, make an appointment with your doctor. “Start with your primary care doctor to get a thorough initial screening,” she says. “They can determine if the condition is serious and refer you to a dermatologist.”