An actinic keratosis is a rough, scaly patch caused by years of sun. It is a precancer, meaning it is the step before skin cancer rather than cancer itself. Most never progress, but most squamous cell carcinomas start as one, which is why they are treated. 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 ultraviolet damage.
Actinic keratoses are rough, scaly areas caused by UV damage to skin cells.
It appears on sun-exposed skin.
They occur most often on repeatedly exposed areas.
It is precancerous.
Some can progress to squamous cell carcinoma.
Some lesions need a biopsy.
Thick, painful, ulcerated or enlarging spots are checked for invasive cancer.
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.
Classic actinic keratosis Rough pink or red scaly spot.
Hypertrophic actinic keratosis Thick, raised and crusted.
Actinic cheilitis Rough, dry patches on the lower lip.
Pigmented actinic keratosis Brown and flat.
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.
Repeated ultraviolet exposure damages the DNA of surface skin cells, allowing abnormal cells to grow within the epidermis. A rough, scaly patch develops, and some lesions can progress to skin cancer.
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.
Actinic Keratosis. Usually develops in adults after years of ultraviolet exposure, especially with fair or immunosuppressed skin.
Warts. Common in children and teenagers; adults can also develop them.
Actinic keratoses are caused by years of ultraviolet light damaging skin cells. They are a warning sign of sun damage.
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 is the biggest risk.
Evidence labels come from each condition’s own treatment list.
An over-the-counter form of vitamin B3, taken as a tablet, which modestly reduced new actinic keratoses and new skin cancers in people at high risk. The effect is real but small, and it stops when the tablets stop. It is an add-on to sun protection and treatment, not a replacement for either. Check with your doctor before starting it.
The lower lip is the site almost nobody protects and one of the higher-risk places for a patch to progress. A balm with SPF 30 or higher, reapplied through the day, is the practical way to cover it. It will not treat a lip that is already persistently dry, scaly or cracked — that needs looking at.
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.
Fluorouracil cream (5-FU). The best-studied cream for treating a whole sun-damaged area rather than single spots, usually applied for two to four weeks. It attacks abnormal cells wherever they are, so it also clears patches that had not surfaced yet. The area becomes red, crusted and sore where those cells were, often revealing more than you knew you had — that reaction is the treatment working, and stopping early leaves the area half treated. If you are pregnant or breastfeeding, ask the doctor managing your pregnancy first.
Imiquimod cream. Prompts your own immune system to clear the abnormal cells, applied a few times a week over a longer course than fluorouracil. It also treats the whole field, and it can suit the face and scalp well. Expect redness and crusting, and sometimes a few days of feeling fluey. The same pregnancy advice applies: ask the doctor managing your pregnancy first.
Tirbanibulin ointment. A newer ointment used once a day for five days on the face or scalp. The short course and the milder reaction are the point of it — most people are through the redness and flaking within a couple of weeks. It is used on a limited area at a time, and long-term results are less well known than for fluorouracil.
An anti-inflammatory gel applied twice a day for two to three months. It is much gentler than fluorouracil, which makes it an option for people who cannot manage a strong reaction on visible skin. It clears fewer patches, and the course is long.
A prescription retinoid people often ask about here, because it is known for sun-damaged skin. It smooths texture and helps the mottled color, but trials have not shown that it clears actinic keratoses or prevents skin cancer. It is reasonable for the look of sun damage, and it is not a treatment for the patches themselves.
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.
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.
An oral retinoid used mainly for organ transplant recipients and others whose immune systems are suppressed, who make large numbers of these patches and progress from them more often. It reduces how many new patches and skin cancers appear while it is taken, and the benefit fades once it is stopped. It has real side effects and needs blood tests. It must never be taken in pregnancy, and pregnancy has to be avoided for three years afterwards.
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.
Freezing with liquid nitrogen is the quickest option for a handful of separate patches, done in a few seconds each with no prescription. It stings sharply, then blisters or crusts and heals over one to three weeks. Its limit is that it only treats what can be seen, so new patches keep arriving from the damaged skin around them. It often leaves a permanently pale mark, which is more noticeable on deeper skin tones — worth asking about before you start.
A light-activated liquid is put on the whole area, left to soak in, then activated with a lamp. It treats a broad field in one or two clinic visits instead of weeks of cream, which suits people who cannot manage a long course at home. The area stings during treatment and is red, swollen and sore for several days, and the treated skin has to be kept out of light straight afterwards.
The thicker, harder patches that freezing struggles with are scraped away under local anesthetic and the base sealed. It is useful when a patch has built up into a lump or a horn, and the scraped material can be sent for testing. It leaves a small scar, and like freezing it treats only the spot in front of you.
A medium-depth peel takes off the damaged top layer across a whole face or scalp at once, so it treats the field rather than single spots. It is an option when creams have not been tolerated. The skin is red and peeling for about a week, and results depend a lot on who is doing it and at what strength.
Not a treatment, but the right answer for a patch that is thick, firm, tender, bleeding, growing quickly, bigger than about a centimeter, forming a horn, sitting on the lip or ear, or unchanged after proper treatment. A few minutes under local anesthetic tells you whether the abnormal cells are still confined to the top layer or have gone deeper. Freezing a patch like that instead removes the evidence without answering the question.
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.
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.
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.
Actinic keratoses are not steady. Individual spots come and go, which is one reason they get dismissed. The trend over years is upward.
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.
Squamous Cell Carcinoma
The skin cancer that these patches can turn into. Any one patch is unlikely to progress in any one year, but most squamous cell carcinomas begin in an actinic keratosis or in the damaged skin around one, and people usually have many patches over many years. Treating patches lowers how many of these appear later. A patch that thickens, hurts, itches, bleeds or grows quickly is sampled rather than frozen.
Actinic cheilitis on the lip
The same sun damage on the lower lip, where it shows up as persistent dryness, scaling, cracking or a lip border that has blurred into the skin. It is easy to read as chapped lips, and lip balm does not fix it. The lip matters more than its appearance suggests, because it is a higher-risk site if a patch progresses, so a dry scaly lower lip that has not settled in a month should be looked at.
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 assessment of persistent rough spots. Rapid growth, tenderness, thickening, ulceration or bleeding raises concern for skin cancer.
Seek assessment for an uncertain, painful, bleeding or changing growth, or persistent warts with weakened immunity. Genital lesions need separate assessment.
No. It is a precancer - abnormal cells in the top layer of skin that have not formed a tumor. A minority become squamous cell carcinoma, and they are treated because most squamous cell carcinomas begin this way.
Low, for any single patch in any single year. Published estimates vary too widely to quote. What matters is cumulative: more patches, for longer, with more sun. A suppressed immune system raises it considerably.
It stings for a few seconds and aches afterward. It blisters or crusts within a day or two and heals over one to three weeks. A pale mark often remains where the skin regrows with less pigment - sometimes permanent, and more noticeable on deeper skin tones.
That is how it works. Fluorouracil and imiquimod provoke a reaction exactly where abnormal cells are, so the area turns red, crusted and sore, often revealing more patches than you knew you had. It settles a couple of weeks after finishing. Stopping early leaves the area partly treated.
New ones almost certainly will, because the sun damage remains. That is not treatment failure. Most people settle into periodic checks, occasional retreatment and daily sun protection - the protection is what reduces how many new ones appear.
A few discrete patches, and freezing is efficient. Many patches, or a whole area of damaged skin, and a cream or photodynamic therapy lasts longer, because it reaches cells that have not surfaced yet. Downtime is part of the choice.
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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