Moles on your skin are normal most of the time. But there are some situations when you should watch your moles and have them checked out by a dermatologist before they grow into cancer. Here are four situations where a mole can put you at risk of developing skin cancer, or melanoma, and what you can do to prevent it.

You Were Born with a Mole

The average person has 10 to 40 moles on their body by the time they are at the age of 30. Moles normally appear and grow during childhood, adolescence, and into your twenties. But, when a person is born with a mole, or congenital nevi, on their body, the mole has a higher chance of becoming a melanoma. 

Only about 1 in 100 people are born with a mole, but if you or your child is born with this type of congenital nevi, you should watch it closely for any signs it is changing. Then, teach your child how to check it often so they can watch it for signs of cancer.

Watch your congenital nevi closely to see if it grows large quickly, changes shape, or develops different colors. These changes can be signs that this birth mole is growing into cancer and it should be checked by a dermatologist and possibly removed as soon as possible. 

If you have a congenital nevi, you may choose mole removal to avoid any problems with cancer or to deal with cosmetic problems.

You Have an Extra-Large Mole

If you have had a mole since birth that has grown larger than the diameter of a pencil eraser, you are at a higher risk for developing skin cancer. This type of birth mole that grows unusually large is called a dysplastic nevi. And, if you have 10 or more dysplastic nevi, you are 12 times more likely to have melanoma.

Watch these dysplastic nevi closely to see if they grow uneven edges, uneven color, or become irregular in shape. Your dermatologist will remove the entire mole including some of the surrounding tissue, stitch up the incision, and have the nevi tissue tested to see if it is melanoma.

Your Mole's Appearance Changed

If all your moles grew during childhood, you still need to watch for any unusual changes in their appearances. Look to make sure your moles are symmetrical. Also, look for any mole borders growing uneven, blurry, or jagged. Check to see if any moles begin to develop different colors, such as patches of blue, tan, white, red, or black, or grow larger than the diameter of a pencil eraser. If any of these changes occur in a mole, it is time to get the mole checked by your dermatologist.

If you have a lot of moles on your body, take a picture of different areas on your body every couple of months, then compare the pictures for any changes in your moles. It can be hard to keep track of what they all look like when you have so many moles on your body, so using the camera on your phone or a digital camera can help you keep track of them.

Your Moles Appeared During Your Adulthood

It is completely normal for your skin to develop new moles during your early life, until age 30. But, if you grow new moles after age 30, there can be higher chance these moles are cancerous. Mole growth after age 30 indicates your skin has been exposed to the sun's harmful rays too much, leading to cancer. 

Watch out for any late-growth moles after you are 30 years old and have them checked by your dermatologist as soon as you discover them. It is most common for men to find melanoma on their chest or back, and women to commonly find melanoma on their lower legs. It is important to pay careful attention to these common spots for melanoma, and also check the skin on any areas of your body that have had extra time in the sun.

Remember these four situations and watch for any melanoma risk in your moles.