Squamous cell carcinoma is the second most common skin cancer. It usually appears as a rough, scaly or crusted bump on skin that has had years of sun, and it often looks like a sore that will not heal. Found early it is removed and cured. Left alone it grows deeper, and a small share spread. Warts are firm, rough growths caused by a common virus that infects the top layer of skin. They are harmless and most of them clear on their own, but they spread easily and they are slow to treat.
The same eight facts on every condition comparison.
It is a skin cancer of keratinocytes.
It arises from the main cells of the outer skin.
It often looks crusted or ulcerated.
It may be a growing scaly lump, persistent sore or tender patch.
Most are treated successfully.
Some can invade deeply or spread to lymph nodes.
Risk is assessed individually.
Size, depth, site and immune status guide care.
They are caused by HPV.
Cutaneous warts are benign growths caused by certain types of human papillomavirus.
They spread by contact.
Warts can pass through direct contact or from one area of skin to another.
Many clear on their own.
Many resolve naturally, especially in children.
Diagnosis is usually visual.
Clinicians look for the rough surface and small capillary dots; uncertain growths may be biopsied.
Squamous cell carcinoma in situ Flat red scaly patch, surface only.
Invasive squamous cell carcinoma Generated illustration. Firm, crusted or ulcerated bump.
Keratoacanthoma Fast-growing dome with a central crater.
Common warts Rough bumps on hands and fingers.
Plantar warts Flat, painful warts on the soles.
Flat warts Small, smooth, flat-topped bumps.
Filiform warts Long, thread-like growths on the face.
DNA changes allow abnormal surface skin cells to multiply, commonly after long-term ultraviolet damage. In invasive squamous cell carcinoma, the cancer grows through the epidermal boundary into the dermis.
Human papillomavirus enters through small skin breaks and stimulates local surface-cell growth. The thickened tissue forms a rough bump that may contain visible dark capillary dots.
Squamous Cell Carcinoma. Usually appears in older adults after cumulative sun damage; immunosuppression can lead to earlier disease.
Warts. Common in children and teenagers; adults can also develop them.
Squamous cell carcinoma starts when DNA damage makes skin cells grow out of control. Ultraviolet light is the main cause.
Warts are caused by the human papillomavirus infecting the top layer of skin. The virus makes skin cells grow faster, forming a rough bump.
Fair skin that burns easily is inherited and raises the risk.
Evidence labels come from each condition’s own treatment list.
The pharmacy sprays get nowhere near as cold as clinic liquid nitrogen, so they work best on small, new, thin warts on the hands and poorly on thick foot warts. They sting and can blister. On deeper skin tones they carry the same risk of leaving a pale or dark mark as clinic freezing does.
Covering a wart with tape for a few days at a time, then filing it, is cheap and harmless, and the trials are genuinely mixed on whether the tape itself adds anything. Any benefit is probably from the covering and the filing. It is reasonable alongside salicylic acid and a poor substitute for it.
The first treatment for almost every ordinary hand or foot wart, and the one with the best evidence outside the clinic. It dissolves the infected thickened skin a layer at a time, so it only works if it goes on every single day. Soak the wart for five minutes, file the dead surface off, apply, and cover it. Twelve weeks is a fair trial; ten days is not.
Imiquimod cream. A cream that works on the last step of the problem: it makes the local immune system pay attention to the virus. It is used mainly for flat warts on the face and for warts that keep coming back, applied a few nights a week for weeks. It reddens and irritates the skin while it works, and it does poorly on thick foot warts.
A retinoid cream used for the flat warts that appear in groups of dozens on the face and the backs of the hands, where acid and freezing would be too harsh over so wide an area. It speeds up the turnover of the infected surface cells. It takes months, and it makes the skin dry and sun-sensitive while it runs.
5-fluorouracil cream. A chemotherapy cream at a low strength, applied to the wart itself, often under tape. It is used for flat warts and for warts that have not shifted with acid, and it is a common choice in children because it does not hurt going on. It reddens and can crust the treated skin, and it is not used in pregnancy.
An old stomach-acid tablet that people ask about for multiple stubborn warts, on the idea that it nudges the immune system. The better-controlled trials found it no more effective than a dummy tablet in adults. It is safe and cheap, so it is occasionally still tried in children, but it should not replace treatment that is known to work.
Candida antigen injection. A tiny amount of yeast protein injected into one wart, to wake the immune system up in that spot. What makes it useful here is that untreated warts elsewhere on the body often clear at the same time, so it suits someone with many warts rather than one. It is repeated every few weeks, and it can cause a day or two of aching or flu-like feeling.
Bleomycin injection. Injected directly into warts that have resisted everything else, particularly thick ones on the soles and around the nails. Clearance rates are good. It is painful enough that the area is numbed first, it can leave a permanent nail change if used at the nail fold, and it is not used in pregnancy, so it sits late in the order for a reason.
The tumor is removed a layer at a time and each layer is checked under the microscope during the same appointment, so the surgeon stops as soon as the edges are clear. It gives the highest cure rate and takes the least normal skin, which is why it is used on the face, ears, lips, hands, feet and genitals, and for large, recurrent or aggressive tumors. It is a long appointment rather than a difficult one.
The standard removal: the tumor is cut out with a margin of normal skin around it and the wound is stitched closed, usually in one visit under local anesthetic. It cures the large majority of straightforward tumors on the trunk, arms and legs. The margins are checked afterwards rather than during, so occasionally a second procedure is needed to clear an edge.
The tumor is scraped out with a small loop and the base is sealed with an electric current, repeated a few times in one sitting. It is quick and effective for small, thin, low-risk tumors on the trunk and limbs. It is not used on the face, on large or recurrent tumors, or anywhere depth matters, because nothing is sent for margin checking and it leaves a round pale scar.
A quick freeze in clinic, used for actinic keratoses and occasionally for a small patch of carcinoma in situ. It is a treatment for the step before this cancer, not for the cancer itself. Freezing an invasive tumor leaves cells behind at depth and hides what is happening under a healing crust.
A light-activated cream treatment for the earliest forms only — actinic keratoses and some cases of carcinoma in situ. It treats a whole patch of sun-damaged skin at once and heals with a good cosmetic result. It has no role in an invasive tumor, and using it on one delays proper removal.
Nothing else on this page happens without it. Even an experienced dermatologist with a dermatoscope cannot settle this by looking, and the report says far more than yes or no — how deep it goes, how aggressive the cells look, whether it is tracking along a nerve. Those details choose the treatment. It takes a few minutes under local anesthetic and leaves a small wound. A biopsy does not make cancer spread.
The wart is numbed, burned with an electric current and scraped away in one visit. It is kept for a single stubborn wart that has failed everything gentler, because it leaves a scar, and a scar on the sole of a foot can hurt more than the wart did. Warts can still regrow at the edge of the scar.
Liquid nitrogen freezes the infected skin and the injury also draws immune attention to the spot. It needs repeating every two to four weeks, usually three or four times, and a wart regrowing from the edge between sessions is normal rather than failure. Over several months its results are broadly similar to salicylic acid used properly. It stings, it blisters, and on deeper skin tones it can leave a lasting pale or dark mark.
A blistering liquid painted on in clinic and washed off a few hours later. It is painless going on, which is why it is a common first choice for children and for warts on the face. The blister that follows lifts the infected skin away over the next few days and can be sore. It usually takes more than one visit.
Paring in clinic. The top dead layer is shaved off with a blade. It does not hurt, because that layer has no nerve supply, and it does two jobs at once: it confirms the diagnosis by exposing the tiny clotted vessels a callus does not have, and it lets acid or liquid nitrogen reach live infected skin. It is done alongside another treatment, never as the whole treatment.
The laser targets the small blood vessels feeding the wart rather than the virus itself. It is an option for stubborn warts on the hands and around the nails when freezing has not worked, and it spares the skin around it, which matters on the face. Several sessions are needed, results are inconsistent, and it is not usually covered by insurance.
Most skin squamous cell carcinomas are cured with appropriate treatment, but they should not be left untreated. Some grow or spread more quickly, especially with immune suppression. Follow-up helps detect recurrence and additional skin cancers.
Warts are self-limiting — they end on their own eventually. In children, roughly two thirds clear within two years without treatment. Adults are slower, and warts present for several years are least likely to go quietly.
A small percentage reach the lymph nodes
A small percentage spread to nearby lymph nodes and occasionally further. Higher risk with large or deep tumors, ear or lip sites, recurrence, and immunosuppression.
Spreading to new spots
An untreated wart seeds others nearby, so one bump becomes a ring of small ones around it, or a line of them along a scratch or a shaving path. Picking, biting and filing several warts with the same file are the usual ways it happens. Covering the wart, keeping your own file and treating early keep the number down.
Color change after treatment
Freezing, and any treatment that blisters or burns, works by injuring the skin, and injured skin can heal a different color. A pale ring around the treated spot can last a year or more and is sometimes permanent, and a dark mark can outlast the wart by months. Both are far more likely on deeper skin tones, which is why gentler treatment and a small test spot are often the better trade.
Warts around and under the nails
Warts that set up in the nail folds are the most stubborn of the group, because the nail shields the virus from creams and from freezing. Left long enough, a wart growing under the nail can lift it or leave a permanent ridge or split in the nail plate. Nail biting and picking at hangnails are how most of them start, and they are the ones most worth taking to a dermatologist early.
Arrange prompt assessment of a persistent scaly, crusted, enlarging or non-healing lesion, especially if tender or bleeding.
Seek assessment for an uncertain, painful, bleeding or changing growth, or persistent warts with weakened immunity. Genital lesions need separate assessment.
It is a real cancer and treated as one. Most cases are cured by removal, which is why the emphasis is on early checks. Untreated, it grows into deeper structures and a small share reach lymph nodes. How serious it gets depends on how long it is left.
Usually weeks to months rather than days or years. The keratoacanthoma variant can appear and enlarge within a few weeks. In immunosuppressed people growth can be much faster, which is why the advice for that group is more urgent.
It depends on the site and how the tumor looks under the microscope. Mohs is generally used on the face, ears, lips, hands, feet and genitals, and for large, recurrent or aggressive tumors. Tumors on the trunk, arms and legs usually get a standard excision.
The treated one can recur, though that is uncommon when margins were clear. Far more common is a new skin cancer elsewhere, because the same damage runs through the rest of the skin. Hence follow-up after a cure.
It substantially raises the odds - many people who have one keratinocyte cancer develop another within a few years. Hence skin checks, daily sun protection and treating actinic keratoses.
Most people do not. Scans and node assessment are reserved for high-risk features - large size, deep invasion, growth along nerves, recurrence, immunosuppression - or an enlarged node. Your dermatologist decides from the pathology report and examination.
Almost nobody can say. The virus lives on warm wet surfaces and passes by skin contact and shared objects, and there is usually a gap of one to six months between catching it and seeing the wart. It is not a sign of poor hygiene.
Probably, eventually. About two thirds of warts in children clear within two years without treatment, and adults are slower. Treating is worth it because warts spread to other spots and other people meanwhile, and older ones are harder to clear.
Freezing removes infected skin but does not reach every infected cell, and it does not teach the immune system to recognize the virus. That is why it takes several sessions two to four weeks apart, and why a wart can regrow from the edge. Regrowth is normal, not treatment failure.
Yes, though not dramatically. The virus passes on shared towels, bath mats, razors, nail clippers and files, and through contact with broken skin. Keeping the wart covered, keeping your own towel and clippers, and wearing something on your feet in shared bathrooms covers most of the risk.
Related viruses, but not the same strains, and they do not usually move between those sites. Genital warts are assessed and treated differently, so do not manage them with hand-wart products.
No. A wart has no root to remove, so cutting reaches live skin without reaching all the virus, and you are left with a scar plus a wart growing back around it. It also risks infection and, on the foot, a wound that heals slowly. Paring is done in clinic with a sterile blade.
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