Q: I have this weird spot on my back that sometimes bleeds and also seems like it’s gotten a little bigger over the past year. Does it sound like skin cancer?

We call these the ABCDEs of melanoma:

• A for asymmetrical (one side looks different than the other)
• B for border (irregular shape vs. smooth and even)
• C for color (more than one color, variegated brown or shades of brown)
• D for diameter (generally more than six millimeters)
• E for evolution (a mole that goes through changes)

Your dermatologist will also do a full-body skin exam to see if you have any other suspicious spots.

Understanding your risk for skin cancer

Skin cancer, or melanoma, is commonly thought to occur in sun-exposed areas of the skin. Surprisingly, however, it can be found in places where we don’t get much sun, such as between the toes and fingers, abdomen or genitals.

The average American has a one-in-five risk over the course of his or her lifetime of developing a skin cancer. Skin cancer is the most commonly diagnosed cancer in the United States and it is the most common form of cancer among young adults ages 25 to 29. Women under 40 are twice as likely to get it as men. It is more likely to develop in men over the age of 50.

If you do have skin cancer, it is highly treatable in the early stages.

How does the sun cause damage to your skin?

Damage to the skin begins early on in life. Each time the sun tans or burns the skin, the change in skin color is actually an “injury” to the structure of your skin. These changes (mutations) over time can lead to the development of a skin cancer. There is no such thing as a “healthy” tan, either from the potential harm of the sun’s rays, or from the exposure in a tanning bed.

Exposure to sun tanning can also accelerate skin aging. One of the immediate effects of tanning is free radical damage to the skin, which contributes to the breakdown of collagen (which gives plumpness to our skin) and elastin (which gives firmness to our skin). The result over time is premature wrinkling and sagging of the skin.

Skin cancer prevention and screening

The recommendations for skin cancer prevention are simple: Use sunscreen, wear a hat or other protective clothing when in direct sun, seek shade, if possible, and avoid intentional tanning.

The American Academy of Dermatology recommends sunscreen with SPF 30 or higher. This number correlates to your “burn rate.” For example, if your skin usually burns within about 15 minutes, the SPF gives you 30 times longer (450 minutes = 7.5 hours) to be in the sun without burning or needing to reapply the lotion.

Unfortunately, we can’t always rely on an all-day approach to sunscreen. In warm weather months we perspire and swim, and the sunscreen product wears off sooner than anticipated. Therefore, you should reapply the lotion every two to four hours or sooner, especially when swimming or being active outdoors.

In order for sunscreen to be effective, you should apply a generous amount. The recommendation is one ounce, or roughly two tablespoons per full-body application. Depending on how much clothing you are wearing you should consider a teaspoon for each exposed skin area.

Although it is not always practical to seek shade, keep in mind that the peak time for the sun’s rays to do their damage is between 10:00 am and 4:00 pm. Therefore, during those hours you need to be more vigilant about exposure and application of sunscreen.

Whether you have been a sun-worshipper your entire life, or if you have been careful to avoid getting a suntan or sunburn, everyone is at risk for developing a skin cancer, whether it is a melanoma or another type, such as a basal cell or squamous cell. Be sure to keep an eye on any suspicious spots and any changes in size, shape or color. This type of self-screening is one of the best ways to detect skin cancer early on while it is still highly treatable. If you have a willing partner, take turns checking each other from time to time.