Warts are non-cancerous viral growths usually occurring on the hands and feet but which can also affect other locations, such as thegenitals or face.[1][3] One or many warts may appear.[3] They are distinguished fromcancerous tumors as they are caused by a viral infection, such as ahuman papillomavirus, rather than acancer growth.[3]
Without treatment, most types of warts resolve in months to years.[1] Several treatments may speed resolution, includingsalicylic acid applied to the skin andcryotherapy.[1] In those who are otherwise healthy, they do not typically result in significant problems.[1] Treatment of genital warts differs from that of other types.[3] Infection with a virus, such asHIV, can cause warts. This is prevented through careful handling of needles or sharp objects that could infect the individual through physical trauma of the skin, plus the practice ofsafe sex using barrier methods such ascondoms. Viruses that are not sexually transmitted, or are not transmitted in the case of a wart, can be prevented through several behaviors, such as wearing shoes outdoors and avoiding unsanitized areas without proper shoes or clothing, such as public restrooms or locker rooms.
Warts are very common, with most people being infected at some point in their lives.[2] The estimated current rate of non-genital warts among the general population is 1–13%.[1] They are more common among young people.[1] Before widespread adoption of theHPV vaccine, the estimated rate of genital warts in sexually active women was 12%.[5] Warts have been described as far back as 400 BC byHippocrates.[4]
A range of types of warts have been identified, varying in shape and site affected, as well as the type of human papillomavirus involved.[6][7] These include:
Common wart (verruca vulgaris),[8] a raised wart with a roughened surface, most common on hands, but can grow anywhere on the body. Sometimes known as a Palmer wart or junior wart.
Flat wart (verruca plana), a small, smooth, flattened wart, flesh-coloured, which can occur in large numbers; most common on the face, neck, hands, wrists, and knees.
Filiform ordigitate wart, a thread- or finger-like wart, most common on the face, especially near the eyelids and lips.
Genital wart (venereal wart,condyloma acuminatum,verruca acuminata), a wart that occurs on the genitalia.
Periungual wart, a cauliflower-like cluster of warts that occurs around the nails.
Plantar wart (verruca,verruca plantaris), a hard, sometimes painful lump, often with multiple black specks in the center; usually only found on pressure points on the soles of the feet and between toes.
Mosaic wart, a group of tightly clustered plantar-type warts, commonly on the hands or soles of the feet.
Warts are caused by thehuman papillomavirus (HPV). There are about 130 known types of human papillomaviruses.[9] HPV infects thesquamous epithelium, usually of the skin or genitals. Each HPV type is typically only able to infect a few specific areas of the body. Many HPV types can produce abenign growth, often called a "wart" or "papilloma", in the area they infect.[10] Many of the more common HPV and wart types are listed below.
Common warts – HPV types 2 and 4 (most common); also types 1, 3, 26, 29, and 57, and others.
Gardasil 6 is anHPV vaccine aimed at preventing cervical cancers and genital warts. Gardasil is designed to prevent infection with HPV types 16, 18, 6, and 11. HPV types 16 and 18 currently cause about 70% ofcervical cancer cases,[13][14] and also cause somevulvar,vaginal,[11]penile andanal cancers.[12] HPV types 6 and 11 are responsible for 90% of documented cases of genital warts.[17]
Gardasil 9 protects against HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58.[18]
HPV vaccines do not currently protect against the virus strains responsible forplantar warts (verrucae).[19]
There are many treatments and procedures associated with wart removal.[21] A review of various skin wart treatments concluded that topical treatments containingsalicylic acid were more effective thanplacebo.[22]Cryotherapy appears to be as effective as salicylic acid, but there have been fewer trials.[22]
Salicylic acid can be prescribed by a dermatologist in a higher concentration than that found in over-the-counter products. Severalover-the-counter products are readily available atpharmacies and supermarkets of roughly two types: adhesive pads treated with salicylic acid, and bottled concentrated salicylic acid andlactic acid solution.
Bleomycin — A more potent chemotherapy drug, can be injected into deep warts, destroying the viral DNA or RNA. Bleomycin is notably not USFDA approved for this purpose. Possible side effects includenecrosis of the digits, nail loss, andRaynaud syndrome. The usual treatment is one or two injections.[25][26]
Dinitrochlorobenzene (DNCB), likesalicylic acid, is applied directly to the wart. Studies show this method is effective with a cure rate of 80%.[medical citation needed] But DNCB must be used much more cautiously than salicylic acid; the chemical is known to causegenetic mutations, so it must be administered by a physician. This drug induces an allergic immune response, resulting ininflammation that wards off the wart-causing virus.[27]
Verrutop verruca treatment is a topical solution made from a combination oforganic acids,inorganic acids, andmetal ions. This solution causes the production ofnitrites, which act to denatureviral proteins and mummify the wart tissue. The difference between Verrutop and other acid treatments is that it does not damage the surrounding skin.
Another product available over-the-counter that can aid in wart removal issilver nitrate in the form of acaustic pencil, which is also available at drug stores. In a placebo-controlled study of 70 patients, silver nitrate given over nine days resulted in clearance of all warts in 43% and improvement in warts in 26% one month after treatment, compared to 11% and 14%, respectively, in the placebo group.[29] The instructions must be followed to minimize staining of skin and clothing. Occasionally, pigmented scars may develop.
Trichloroacetic acid can be used to treat warts if salicylic acid or cryotherapy fail or are not available. It requires repeat treatments every week or so. Side effects are burning and stinging.[30]
Twoviral warts on a middle finger, being treated with a mixture of acids (like salicylic acid) to remove them. A white precipitate forms on the area where the product was applied.
Throat warts before and after carbon dioxide laser treatment.
Cryosurgery orcryotherapy, which involves freezing the wart (generally withliquid nitrogen),[39] creating a blister between the wart andepidermal layer after which the wart and the surrounding dead skin fall off. An average of three to four treatments is required for warts on thin skin. Warts on calloused skin, like plantar warts, might take dozens or more treatments.[40]
Laser treatment – often with apulse dye laser orcarbon dioxide (CO2) laser. Pulse dye lasers (wavelength 582 nm) work by selective absorption by blood cells (specificallyhemoglobin). CO2 lasers work by selective absorption by water molecules. Pulse dye lasers are less destructive and more likely to heal without scarring. CO2 laser works by vaporizing and destroying tissue and skin. Laser treatments can be painful, expensive (though covered by many insurance plans), and not extensively scarring when used appropriately. CO2 lasers will requirelocal anaesthetic. Pulse dye laser treatment does not needconscious sedation or local anesthesia. It takes 2 to 4 treatments, but can be many more for extreme cases. Typically, 10–14 days are required between treatments. Preventive measures are important.[40]
Infrared coagulator – an intense source of infrared light in a small beam like a laser. This works essentially on the same principle as laser treatment. It is less expensive. Like the laser, it can cause blistering, pain, and scarring.[41]
Duct tape occlusion therapy involves placing a piece ofduct tape over the wart. Themechanism of action of this technique still remains unknown. Despite several trials, evidence for theefficacy of duct tape therapy is inconclusive.[44][45] Despite the mixed evidence for efficacy, the simplicity of the method and its limited side-effects lead some researchers to be reluctant to dismiss it.[46]
No intervention. Spontaneous resolution within a few years can be recommended.[47]
This image shows throat warts (papillomas) before treatment and during the treatment process. Left to right: warts before treatment, warts on the day ofsilver nitrate treatment, warts two days after treatment, warts four days after treatment, warts six days after treatment, and warts remaining nine days after treatment.
A variety of traditionalfolk remedies and rituals claim to be able to remove warts. According toEnglish folk belief, touchingtoads causes warts; according to aGerman folk belief, touching a toad under afull moon cures warts.[50] The most commonNorthern Hemisphere toads have glands that protrude from their skin that superficially resemble warts. Warts are caused by a virus, and toads do not harbor it.[51]
InThe Adventures of Tom Sawyer,Mark Twain has his characters discuss a variety of such remedies. Tom Sawyer proposes "spunk-water" (or "stump-water", the water collecting in the hollow of a tree stump) as a remedy for warts on the hand. In his version, one puts one's hand into the water at midnight and says:
Barley-corn, barley-corn, injun-meal shorts, Spunk-water, spunk-water, swaller these warts
One would then "walk away quick, eleven steps, with your eyes shut, and then turn around three times and walk home without speaking to anybody. Because if you speak the charm's busted." This is given as an example ofHuckleberry Finn's planned remedy, which involves throwing a dead cat into a graveyard as a devil or devils comes to collect a recently buried wicked person. Another remedy involved splitting a bean, drawing blood from the wart and putting one of the bean halves against the wart, and burying that half at acrossroads at midnight. Thetheory of operation is that the blood on the buried bean will draw away the wart.[52] Twain is recognized as an early collector and recorder of genuineAmerican folklore.[53]
Similar practices are recorded elsewhere. InLouisiana, one remedy for warts involves rubbing the wart with apotato, which is then buried; when the "buried potato dries up, the wart will be cured".[54] Another remedy similar to Twain's is reported fromNorthern Ireland, where water from a specific well onRathlin Island is credited with the power to cure warts.[55]
The cause of warts was initially disputed in the medical profession. In the early 18th century, the physicianDaniel Turner, who published the first book ondermatology, suggested that warts were caused by damagednerves close to the skin. In the mid-18th century, the surgeonJohn Hunter popularized the belief that warts were caused by a bacterialsyphilis infection. The surgeonBenjamin Bell documented that warts were caused by a disease entirely unrelated to syphilis, and established acausal link between warts and cancer. In the 19th century, thechief physician ofVerona Hospital established a link between warts andcervical cancer in particular. But in 1874, it was noted by the dermatologistFerdinand Ritter von Hebra that while various theories were advanced by the medical profession, the "influences causing warts are still very obscure".[56]
In 1907, the physician Giuseppe Ciuffo first demonstrated that a viral infection causes warts. In 1976, the virologistHarald zur Hausen was the first to discover that warts were caused by thehuman papillomavirus (HPV). His continuous research established the evidence necessary to develop anHPV vaccine, which first became available in 2006.[56]
^Adigun, Chris G."Verruca Vulgaris".Merck Manuals. Retrieved16 December 2022.
^De Villiers, E. M.; Fauquet, C.; Broker, T. R.; Bernard, H. U.; Zur Hausen, H. (June 2004). "Classification of papillomaviruses".Virology.324 (1):17–27.doi:10.1016/j.virol.2004.03.033.PMID15183049.
^Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Mitchell, Richard (2007). "Chapter 19: The Female Genital System and Breast".Robbins Basic Pathology (8 ed.). Philadelphia: Saunders.ISBN978-1-4160-2973-1.
^Dhinsa, Arpreet; Philip, Gladis; Daknish, Fatima; Amin, Sahil; Vlahovic, Tracey (September 2023). "42057 Microwave Therapy for Plantar Warts: A Chart Review".Journal of the American Academy of Dermatology.89 (3): AB64.doi:10.1016/j.jaad.2023.07.259.ISSN0190-9622.
^Salman, Samer (2019). "Intralesional Immunotherapy for the Treatment of Warts: A Network Meta-analysis".Journal of the American Academy of Dermatology.80 (4): 922–930.e4.doi:10.1016/j.jaad.2018.07.003.PMID30003983.S2CID51617793 – via Elsevier Science Direct.
.jpg)
