Seborrhoeic keratoses. What they are, and why they appear.

What exactly is a seborrhoeic keratosis?

A seborrhoeic keratosis is a harmless, raised growth of the upper layer of the skin that appears with age. It looks waxy or scaly, ranges from pale tan to dark brown or black, and seems to sit stuck on to the surface rather than buried in it. Dermatologists describe them as appearing to "stick on to the skin surface like barnacles", which is the picture most people recognise once they hear it.

You can usually feel one. Run a fingertip over it and the surface has texture, slightly rough or waxy, a little raised above the skin around it. That raised, on-the-surface quality is the single most useful thing to notice, and it is what separates a seborrhoeic keratosis from the flat marks that come with sun and age.

They are benign. A seborrhoeic keratosis is not premalignant, which means it is not a growth on its way to becoming skin cancer. It is simply one of the things skin does over time. The one caveat comes further down, under when to get a spot checked, but the headline is reassuring: on its own, this is a harmless growth.

Why do I keep getting seborrhoeic keratoses?

Seborrhoeic keratoses come with age and tend to run in families. More than ninety percent of people over the age of sixty have one or more. If you have started noticing them, you are in very ordinary company.

The exact trigger is not fully understood, but age and genetics are the strongest threads. If your parents had a scattering of them, you are more likely to as well. They are not a sign that anything is wrong, not a marker of ill health, and not something you caused.

One thing they are not is sun damage in the way flat pigmentation is. Freckles, sun spots and age spots are the skin reacting to years of light. A seborrhoeic keratosis is a different process, a thickening of the surface layer, which is why it feels raised rather than sitting flat. That difference matters for treatment, and it is worth holding on to.

Why is it called an age wart if it is not a wart?

A seborrhoeic keratosis is often called an age wart because it can look warty, but it is not a wart. It is not caused by a virus and it cannot be passed on to anyone. The nickname describes the look, not the cause, and the cause is where the confusion does real harm.

Warts are caused by the human papillomavirus (HPV). They are contagious, they can spread to other parts of your own skin, and they turn up most on hands and feet. A seborrhoeic keratosis is none of those things. There is no virus involved, nothing to catch, and nothing to give to the people you live with.

So if you have been keeping a growth covered, or worrying that it might spread to your partner or children, you can let that go. It is a harmless thickening of your own skin, not an infection.

Do seborrhoeic keratoses spread or multiply?

Seborrhoeic keratoses do not spread the way an infection does. New ones can appear over time, but each one develops on its own, not by spreading from another. It is common to collect several over the years, which is why people often think they are watching one growth multiply.

This is one of the most reassuring facts to take away. A seborrhoeic keratosis is not seeding the ones that appear later. Removing one does not stop new ones forming elsewhere, because there was never a chain to break, but it also means a single growth is not a sign of more to come on that exact spot.

What does a seborrhoeic keratosis look like as it grows?

A seborrhoeic keratosis usually starts small and pale, then slowly thickens and darkens, becoming more raised and more waxy over months to years. It is a slow, steady change, not a sudden one. The colour can deepen to dark brown or black, and the surface can take on a rougher, more crumbly look.

That slow thickening is normal for these growths. What is worth a second look is anything that changes quickly, bleeds without being knocked, or starts to look very different from the others on your skin. A seborrhoeic keratosis can, once in a while, resemble something that deserves a closer look, so a growth that is genuinely changing is a reason to have it checked rather than to assume. There is a short section on exactly when to do that below, and a separate guide on telling a seborrhoeic keratosis apart from a melanoma.

Not a flat age spot: how to tell the difference

The difference between a seborrhoeic keratosis and a flat age spot is texture, not colour. An age spot is flat and sits level with the skin, so you can see it but not feel it. A seborrhoeic keratosis is raised and waxy, so you can feel its texture with a fingertip. Both can be brown, which is exactly why people mix them up, but the surface gives it away.

This distinction decides which kind of treatment fits, and which guide is the right one for it. A raised, waxy, stuck-on growth is a seborrhoeic keratosis, and that is what this page and the seborrhoeic keratosis removal page are about. A flat, level brown mark is pigmentation, such as a sun spot or age spot, and that is a different concern with a different approach. If your mark is flat, our Pigmentation Guide is the place to start.

Holding that line, raised and waxy here, flat and level there, is the quickest way to know what you are actually looking at.

Can you remove a seborrhoeic keratosis at home?

Removing a seborrhoeic keratosis at home is not a good idea. A benign growth can occasionally resemble something more serious, and a clinician's eye is part of what keeps removal safe. Picking, scraping or trying a chemical from a kit risks infection, scarring and an incomplete result, and it removes the one safeguard worth keeping, a trained look at the growth first.

At-home and over-the-counter kits do exist. The case for having it done in clinic is simple: the growth is assessed before anything is touched, the removal is controlled, and the surrounding skin is looked after. That matters more on a growth that can mimic other things than it does on, say, a callus.

If a seborrhoeic keratosis is bothering you, the cleaner path is to have it looked at and removed properly rather than to improvise at home.

How are seborrhoeic keratoses removed?

At Pink, seborrhoeic keratoses are removed with a Fotona Er:YAG laser, which lifts the growth layer by layer at the surface. Most are cleared in one or two sessions, with thicker growths or a cluster on the neck planned across a short course. The aim is a clean result with as little disturbance as possible to the skin around the growth.

The Er:YAG laser works at a wavelength of 2940 nm, which is absorbed almost entirely at the surface of the skin. That is what lets a clinician remove the raised, waxy tissue in careful passes while keeping heat to the skin around it low. Working progressively, layer by layer, tends to leave a cleaner result than freezing, with a lower chance of a pale or dark mark afterwards. That lower risk of a mark matters most on deeper skin tones, and the right protocol is calibrated for your skin at your consultation.

Removal is a cosmetic choice, not a medical necessity. A seborrhoeic keratosis does not need to be removed for your health. People choose to have one treated when it catches on clothing or jewellery, when it is in a spot that bothers them, or simply when they would rather it was gone. A removed growth does not return at that spot, although new ones can still appear elsewhere over time. If a growth is bothering you and you would like it assessed, you can book a free consultation to talk through removal.

When should you get a spot checked?

You do not need a skin check to have a clearly benign seborrhoeic keratosis removed, but there are times to have a growth looked at first. Pink does not diagnose skin cancer, and no one can tell for certain whether a growth is harmless just by looking, so anything in the list below is a reason to see a GP or skin-cancer clinic before you think about cosmetic removal.

• A spot that is changing in size, shape or colour
• A growth that bleeds, itches or crusts without being knocked
• A very dark spot, or one with several different colours in it
• A mark that looks clearly different from the others on your skin, the "odd one out"
• Any new spot that appears after the age of around twenty-five and keeps changing

If a growth is changing, very dark or unusual, have it checked by a GP or skin-cancer clinic first. Once it is confirmed benign, cosmetic removal is straightforward. There is more on telling a seborrhoeic keratosis apart from a melanoma, and on what these warning signs mean, in our guide on seborrhoeic keratosis or melanoma.

Book your free consultation

If a seborrhoeic keratosis is bothering you, the simplest next step is a free consultation. A clinician looks at the growth, confirms it is the kind that is straightforward to treat, and talks you through removal with the Er:YAG laser. You can book your free consultation online, or read more about the treatment itself on our seborrhoeic keratosis removal page.

Frequently Asked Questions

What exactly is a seborrhoeic keratosis?

A seborrhoeic keratosis is a harmless, raised growth of the upper layer of the skin that develops with age. It looks waxy or scaly, ranges from pale tan to dark brown, and seems to sit stuck on to the surface like a barnacle. You can usually feel its texture with a fingertip. It is benign and is not a growth on its way to becoming skin cancer.

What causes seborrhoeic keratoses, and why am I getting them?

They come with age and tend to run in families. More than ninety percent of people over the age of sixty have one or more. The exact trigger is not fully understood, but age and genetics are the strongest factors. They are not caused by sun the way flat age spots are, and they are not a sign that anything is wrong.

Why is it called an age wart if it is not a wart?

The nickname describes the warty look, not the cause. A seborrhoeic keratosis is not caused by a virus, is not contagious, and cannot be passed on to anyone. Warts, by contrast, are caused by the human papillomavirus (HPV) and can spread. There is nothing to catch and nothing to give to the people around you.

Do seborrhoeic keratoses spread or multiply?

No. They do not spread the way an infection does. New ones can appear over time, but each develops on its own rather than by spreading from another growth. It is common to collect several over the years, which is why people sometimes think one is multiplying.

Can you remove a seborrhoeic keratosis at home?

It is not advised. A benign growth can occasionally resemble something more serious, so a clinician's eye is part of what keeps removal safe. Home removal risks infection, scarring and an incomplete result. The cleaner path is to have the growth assessed and removed properly in clinic.

How are seborrhoeic keratoses removed?

At Pink they are removed with a Fotona Er:YAG laser, which lifts the growth layer by layer at the surface in careful passes. Most are cleared in one or two sessions, with thicker growths or a cluster on the neck planned across a short course. A removed growth does not return at that spot, though new ones can appear elsewhere over time.

Do seborrhoeic keratoses need to be removed?

No. A seborrhoeic keratosis does not need to be removed for your health. Removal is a cosmetic choice, for when a growth catches on clothing, sits in a spot that bothers you, or you would simply rather it was gone.