May is Skin Cancer Awareness Month. According to the Skin Cancer Foundation Web site, skin cancer is the most common type of cancer in the United States. One in five Americans develops skin cancer during his or her lifetime.

Diagnosis rates of melanoma, the most aggressive form of skin cancer, have increased over the past 30 years. This is likely due to high levels of tanning, particularly among 15- to 29-year-olds, according to the American Academy of Dermatology.

Dr. Kenneth Bielinski, a dermatologist in Orland Park, Ill., said everyone should get in the habit of wearing sunscreen and a hat when exposed to direct sunlight. This is the easiest way to prevent the most prevalent forms of skin cancer. He also advised applying sunscreen 30 minutes before leaving the house during daylight.

Bielinski explained there are three different types of skin cancer. The most common, basal cell carcinoma, is also the least aggressive. This affects the bottom part of the skin’s top layer, known as the epidermis, and produces clear or skin-colored spots.

“[It] looks like a pimple that didn’t heal,” Bielinski explained.

Basal cell carcinoma can result from long-term exposure over years, as can squamous cell carcinoma. This type of skin cancer is slightly more aggressive than the basal cell carcinoma, and usually originates in the fatty tissues below the skin. It is marked by red or rough spots on the skin.

Dr. Charles Zugerman, a dermatologist and associate professor of clinical dermatology at the Feinberg School of Medicine at Northwestern University, said both basal and squamous cell carcinomas tend to occur in areas such as the face, ears, chest and back.

“These are the places where people get sun [the most],” Zugerman said.

Squamous cell carcinoma tends to show up in people aged 40 or older, he added.

The third type of skin cancer, melanoma, is the most serious and can target anyone and be found anywhere on the body, Zugerman said, though the chest and back are most common.

The first two types of skin cancer can be treated by simply removing the infected tissue, he said. Melanoma usually requires specialized surgery because it can easily spread to other organs, he said. If the cancer has spread, radiation or immunotherapy may be necessary.

While melanoma cannot be prevented, the squamous and basal cell carcinomas can, because both are caused by overexposure to sunlight.

“Tanning is burning, whether you see burning or not,” Zugerman said. “Little [visible skin] damage still causes problems.”

Zugerman compared any exposure to the ultraviolet rays from the sun to being an occasional smoker; even if you only casually smokes cigarettes, it still has the potential to negatively affect your health,  he said.

“Consider [sunlight] as radiation, even if it feels good,” he said. “Protect yourself; that’s how you look best.”

Dr. Meyer Horn, a dermatologist, partner at the Dermatology & Aesthetics of Wicker Park and clinical instructor of dermatology at the Feinberg School of Medicine at Northwestern, said there is no such thing as a healthy tan and recommended everyone wear a hat and big sunglasses when exposed to direct sunlight.

“It’s very, very appropriate … to get spray tanning if it keeps people from wanting to get a real tan,” Horn said. “Use tan in a can.”

For people who still wish to continue tanning in the sunlight or tanning beds, Horn said he will switch methods of persuasion.

“For patients not swayed, we lean on other scare tactics, like the incredible potential aging on the skin,” he said. “It is unbelievable.”

Constant tanning leads to premature aging of the skin, he explained. Skin will wrinkle and begin to appear leathery.

For people exposed to sunlight, Horn said it is important to buy broad spectrum sunscreen, which prevents against the two different kinds of ultraviolet light, UVA and UVB. The SPF of the sunscreen refers to its protection from UVB rays, which causes exposed skin to burn. Though SPF doesn’t measure the level of protection of UVA rays, these are known to contribute to skin cancer.

Sunscreen should also be reapplied every 90-120 minutes, and more often if the individual has been swimming or sweating.

Bielinski recommended a minimum of 30 SPF for everyone, regardless of skin color. He added that the majority of people do not use the recommended amount of sunscreen, applying much less than they should.

Zugerman said those with fair skin should use 100 SPF. He said a higher SPF is recommended because as the sunscreen shields skin from the sunlight, it loses its efficacy.

“Sunscreen dies to help you,” he said. “After an hour, a 30 SPF becomes a 5.”

Protecting oneself against sun exposure is not the only way to prevent skin cancer, Horn said. It is also important to track moles on one’s skin; the more moles a person has, the higher his or her risk is of developing melanoma.

“Beauty marks … or that old mole with hair sticking out of it that you’ve had for years, are unlikely to be a problem,” he said.

Moles that are very dark, unusually shaped or experience a change in any characteristics should be viewed as suspicious, Horn explained. Often, melanoma develops within existing moles.

“Every mole is a benign tumor,” he said.

According to Horn, raised moles are not as much of a problem as the darker, flatter ones. While this is not a cause for worry, this does mean that an individual should carefully monitor all moles, or have a loved one help conduct a monthly examination for changes.

Horn said primary prevention by tracking moles and avoiding exposure to the sun is the best way to prevent skin cancer. He also said many people try to reverse signs of aging as they get older, hoping to preserve their youth, but rather than contributing to the damage, it is important to take care of one’s skin now.

“Be super proactive,” Horn said.