Ask Harvard Medical School Videos

Spotting skin cancer

How can you tell if a mole is cancerous or not?

How can you tell if a mole is cancerous or not?

Well moles, or as health professionals call them, nevi, are growths on the skin. They’re either flat or raised, round or oval, can be brown, pink, or skin colored, and are usually smaller than the head of a pencil eraser. Most people have between 10-40 moles and each one has its own life cycle. You may have a few in early childhood but many more usually appear during puberty and peak in number in your 20’s and 30’s. And yes, they can change. They can grow in size or go from being flat to raised. Your job is to watch for the kind of changes that signal an atypical mole that could develop into melanoma, which is a potentially deadly skin cancer. When you assess your moles, think A, B, C, D, E changes. A is for asymmetry. If you cut the mole in half, does one side look different from the other. B is for border irregularities. See how jagged this side is. C is for color changes, such as a mole getting darker or having varying shades of color. D is for diameter. Moles larger than a pencil eraser are suspicious; although, many normal moles can be larger or atypical moles can be smaller. E is for evolution. Any rapidly changing mole or symptoms, such as bleeding, itching, and pain, should be checked. If you burn easily, have red hair, freckles, more than 50 moles, or a family history of melanoma, you should be especially diligent. Skin checkups by your doctor are really a good idea for everyone since early detection could prevent a life-threatening skin cancer. From Harvard, I wish you good health.

Learn more about our
health content.