While most moles are harmless, some moles have a higher risk for progressing to malignant melanoma which is a potentially deadly skin cancer. Like most people, you probably have at least a few moles on your skin. How do you know if your moles are dangerous? To start with, you should use the rule of ABCDE's to help evaluate your moles:
Asymmetry - A benign mole is usually symmetric. If you draw a line through the middle of the mole, the two sides should match. Malignant melanoma is often asymmetric with two sides that do not match.
Border - A benign mole usually has a smooth, even, distinct border. Malignant melanoma often has a jagged, irregular border or a border which is indistinct and not crisp.
Color - Most benign moles are all one color, usually a single shade of brown. Melanoma often has a mix of colors such as light brown, dark brown, pink, dark blue, or white.
Diameter - Benign moles usually are smaller in size and are typically not larger than 6 mm or a pencil eraser.
Evolving - If a mole starts to evolve or change, or if a new mole develops, this can be a worrisome sign. Normal moles typically do not grow or change with time.
Any mole which looks suspicious based on the ABCDE criteria should be checked promptly by a dermatologist.