Three common things appear on skin, they get confused constantly, and the treatment for each is different. A skin tag is a friction-driven growth of ordinary skin. A wart is caused by a virus. A mole is a cluster of pigment cells. Nothing about the three is interchangeable.
What follows explains what each one is and how they typically differ. It is not a way to identify your own, and the last section explains why that distinction matters more than it might seem.
What is a skin tag?
A soft growth attached to the skin by a narrow stalk, made of the same tissue as the skin around it. Skin tags hang rather than sit, they are usually skin-coloured or slightly darker, and they are painless unless something catches them.
They form where skin rubs, which is why they cluster on the neck, underarms, eyelids, under the breasts and in the groin. Friction, age and genetics account for most of it. They are benign and they do not become cancerous.
What is a wart?
A growth caused by human papillomavirus infecting the top layer of skin. That single fact accounts for most of how warts behave and how they differ from the other two.
Warts are firm rather than soft, rough rather than smooth, and they sit flat against the skin or raised from it rather than hanging from a stalk. Many have a grainy surface, and some show small dark points, which are tiny clotted blood vessels rather than the roots people often assume.
Because a virus causes them, warts do things the other two never do. They can spread to other parts of your own body and to other people, they appear in clusters, and they sometimes resolve on their own once the immune system deals with the infection. A verruca is the same thing on the sole of the foot, pushed flat by body weight and often painful for that reason.
What is a mole?
A cluster of melanocytes, the cells that produce pigment. Most people have between ten and forty, most appear during childhood and adolescence, and the overwhelming majority are entirely harmless.
Moles are pigmented, usually brown or black though some are closer to skin tone, and they are typically round or oval with a defined edge. They can be flat or raised, and some carry hair, which is normal and not a warning sign.
Moles are the one of the three that warrants ongoing attention, because melanoma develops from melanocytes. That does not mean moles are dangerous. It means changes in them are worth having looked at, which is a different statement.
How they typically differ
Broadly, and with the caveat in the next section:
- Texture. Skin tags are soft and move easily. Warts are firm and rough. Moles are usually smooth, flat or gently raised.
- Attachment. Only skin tags hang from a narrow stalk. Warts and moles sit against the skin.
- Colour. Skin tags match the surrounding skin or sit slightly darker. Warts are usually skin-coloured or greyish. Moles are pigmented.
- Spread. Warts spread, because a virus causes them. The other two do not.
- Location. Skin tags favour skin folds. Warts favour hands, feet and areas of broken skin. Moles appear anywhere.
Why this list is not a diagnostic tool
Every description above says usually, typically or broadly, and that is deliberate. Lesions do not read the textbook. Skin tags can become firm when irritated. Warts sometimes appear on a narrow base that looks like a stalk. Moles can be raised, soft and skin-coloured, and some warts darken enough to be mistaken for one.
More importantly, other things exist that resemble all three. Seborrhoeic keratoses are extremely common, entirely benign and frequently mistaken for moles. Several conditions that need proper attention can also present as an unremarkable-looking bump. Distinguishing them is not about knowing the list better; it is about examining the lesion, often with magnification, and knowing what the uncommon things look like.
The practical version: if you already know something is a skin tag because you have had a dozen of them in the same place for years, that knowledge is reasonable. If you are looking at something new and trying to work out which category it falls into, that uncertainty is the answer. Have it examined.
When to see a doctor rather than read about it
Book an appointment if a growth is new and you are unsure what it is, if an existing one changes in size, shape or colour, if it bleeds without being caught on anything, if it itches or becomes painful, or if it simply looks different from the others you have.
None of those means something is wrong. All of them mean a doctor should look rather than you deciding. That is a five-minute appointment, and the alternative is a delay that only matters in the small number of cases where it matters enormously.
Why the treatments differ
Because the causes differ, treating one as though it were another does not work.
Skin tags are removed physically, by freezing, excision at the base under local anaesthetic, or electrosurgery. Removal is straightforward and the tag does not return, though friction may produce new ones nearby over time.
Warts need the viral infection addressed as well as the growth. Cryotherapy is common, sometimes over several sessions, and recurrence is more likely than with the other two because the virus can persist in the surrounding skin. Treating a wart as though it were a skin tag, by cutting it off, leaves the infection in place and risks spreading it.
Moles are the category where method matters most. Where there is any question about a mole, it is removed by excision so the tissue can be sent for examination, rather than by a method that destroys it. Freezing or burning off a mole means nobody can ever examine what it was, which is the single strongest argument against home removal kits and against anyone offering to remove a pigmented lesion without examining it first.
Having it looked at
Removal at Pulse Light Clinic is doctor-led, and the assessment comes before any decision about method. Establishing what something is decides how it should be treated, and in the case of pigmented lesions it decides whether it should be sent for examination afterwards.
Pulse Light Clinic is CQC-registered and doctor-and-nurse-led, and has been treating patients in London since 2001.
Book a consultation to have any lesion examined before deciding on removal.
