Aging Spots: What Those “Barnacles” Really Are

Matthew Zook MD, PhD, FAAD

Got spots on your skin? If you’re alive and have skin, chances are you have a few. They can come in all different sorts of colors, sizes and shapes. Some are good, some are bad; some look fine, others – not so much.

If you’re of a certain age, meaning old enough to understand that euphemism, you probably have these new “moles” that keep popping up. Black, brown, grey or white, usually raised, often dry and scaly. They usually come up on the back, chest, cheeks or hairline but can arise anywhere. They seem to have a mind of their own, appearing when and where they want. I’ve been doing this Dermatology bit for a while now and I have yet to meet anyone who loves them and are glad they’re there.

What Are Age Spots?

The technical term is Seborrheic Keratosis (Seborrheic Keratosis if you have a more European flair) or SK for short. Other common terms used for them are warts, tags, and barnacles. None of these terms are really great to describe them. They are not virally induced like real warts. Tags are appendages of normal skin, SK’s are abnormal. Even seborrheic isn’t a great term as they are neither associated with sebaceous glands or limited to a seborrheic distribution (face, nasal sidewalls, chest). Perhaps barnacles is the best description because they are rough and crusty and the longer you’re around the more likely you are to get them.

SK’s are clonal proliferations of keratinocytes, meaning they are growing abnormally, but are not cancerous. They are benign. Keratinocytes are the cells that make up most of the skin and go through an elegant maturation process as they transit from the bottom layer to the top. This doesn’t happen in SK’s, the cells tend to keep immature characteristics. Perhaps this is why they look like they do, they heap up upon themselves resulting in hyperkeratosis which is the term for the rough thickened texture they tend to have.

It’s not clear why they don’t mature though. Many have an activating mutation in the fibroblast growth factor receptor 3 gene which codes for a protein that plays a role in cell division. Logically this could explain the clonal proliferation, but a lot remains to be worked out until we have a complete understanding. We do know that there is a strong family tendency for them to arise, so if you have them, thank Mom and Dad.

How to Treat Age Spots

There are several different ways that they can be treated. Mostly however, they are left alone as they don’t pose any malignant potential. If they do need to be addressed, they can be treated with cryotherapy (freezing them with liquid nitrogen at -320 F) or curetted (removing the top layer of skin with a special instrument) or shaved off after anesthetizing with an injection of lidocaine. Less commonly they can be removed with a chemical peel or laser. All these approaches have their pros and cons but tend to be effective.

When are Age Spots a Problem?

Here’s the catch with SK’s. We tell you to watch out for new lesions that arise as you go through life. And the spots you have should not change color, or have an irregular border, and not grow too much or change. SK’s do all of those. And they can look A LOT like real moles and when real moles do those things it can be a warning sign for the development of melanoma. So what’s a person to do? You have these new spots, are they good or are they bad? Do you have to worry about them? Can they be made to go away?

Well, that’s what we’re here for. Let us take a look at them with you. We’re pretty good at differentiating the good from the bad. And we can talk over the options for treating them and help you decide what’s best.