Melanoma often develops in an existing mole of any size. If you notice an asymmetrical mole, a mole with an irregular border, a mole that has changed color, or a mole that has a diameter greater than five millimeters (the size of a pencil eraser), see your doctor. Not all mole changes signal melanoma, but it's important to have any changes checked out early.
Bleeding, pain or ulcerations are usually a sign that a mole may have become a melanoma.
It's also important to know that the risk of melanoma increases with age. Make sure your health professional does a thorough skin exam at least once per year. That includes a look at the top of your ears and your scalp. If you are very fair, a twice-yearly exam may be in order. Your doctor will help you with that decision.