Aplantar wart(also known as "Verruca plantaris":405) is awartcaused by thehuman papillomavirusoccurring on the sole or toes of the foot. (HPV infections in other locations are not plantar; seehuman papillomavirus.) Plantar warts are usuallyself-limiting, but treatment is generally recommended to lessen symptoms (which may include pain), decrease duration, and reduce transmission.
It is estimated that 7–10% of the US population is infected. Infection typically occurs from moist walking surfaces such as showers or swimming pools. The virus can survive many months without a host, making it highly contagious.
Plantar warts are benignepithelialtumorscaused by infection by human papilloma virus types 1, 2, 4, or 63. These types are classified as clinical (visible symptoms). The virus attacks the skin through direct contact, entering through possibly tiny cuts and abrasions in thestratum corneum(outermost layer of skin). After infection, warts may not become visible for several weeks or months. Because of pressure on the sole of the foot or finger, the wart is pushed inward and a layer of hard skin may form over the wart. A plantar wart can be painful if left untreated.
Warts may spread throughautoinoculation, by infecting nearby skin or by infecting walking surfaces. They may fuse or develop into clusters called mosaic warts.
A plantar wart is a small lesion that appears on the sole of the foot and typically resembles acauliflower, with tiny blackpetechiae(tinyhemorrhagesunder the skin) in the center. Pinpoint bleeding may occur when these are scratched, and they may be painful when standing or walking.
Plantar warts are often similar tocallusesor corns, but can be differentiated by close observation of skin striations. Feet are covered in skin striae, which are akin tofingerprintson the feet. Skin striae go around plantar warts; if the lesion is not a plantar wart, the cells'DNAis not altered and the striations continue across the top layer of the skin. Plantar warts tend to be painful on application of pressure from either side of the lesion rather than direct pressure, unlike calluses (which tend to be painful on direct pressure instead).
Because plantar warts are spread by contact with moist walking surfaces, they can be prevented by not walking barefoot in public areas such as showers or communal changing rooms (wearing flip flops or sandals helps), not sharing shoes and socks, and avoiding direct contact with warts on other parts of the body or on other people. Humans build immunity with age, so infection is less common among adults than children.
As warts are contagious, precautions should be taken to avoid spreading them. The BritishNational Health Servicerecommends that children with warts:
Once a person is infected, there is no evidence that any treatment eliminates HPV infection or decreases infectivity, and warts may recur after treatment because of activation of latent virus present in healthy skin adjacent to the lesion. There is currently no vaccine for these types of the virus[dubious–discuss]. However, treatments are sometimes effective at addressing symptoms and causingremission(inactivity) of the virus.
Some treatments that have been found to be effective include:
ImmunotherapyIntralesional injection of antigens (mumps,candidaortrichophytinantigens USP) is a new wart treatment which may trigger a host immune response to the wart virus, resulting in wart resolution. Distant, non-injected warts may also disappear.
ChemotherapyTopical application of diluteglutaraldehyde(a virucidal chemical, used for cold sterilization of surgical instruments) is an older effective wart treatment. More modern chemotherapy agents, like 5-fluoro-uracil, are also effective topically or injected intralesionally.Retinoids, systemically (e.g.isotretinoin) or topically (tretinoincream) may be effective.
A ~7mm plantar wart surgically removed from patient's footsole after other treatments failed.
A common surgical method involvescryosurgeryusingliquid nitrogen; this method produces a blister under the wart.Electrodesiccationand surgical excision produce scarring. If the wart recurs, the patient has a permanent scar along with the wart.Laser surgerymay be effective. Especially effective is the use of the 585 nm pulsed dye laser. It is the most effective treatment of all and does not leave scars, but it is generally a last resort treatment, as it is expensive and painful, and multiple laser treatments are required (generally 4-6 treatments repeated once a month until the wart disappears).Cauterizationmay be effective as a prolonged treatment. As a short-term treatment, cauterization of the base with anaesthetic can be effective, but this method risks scars orkeloids. Subsequent surgical removal is unnecessary, and risks keloids and recurrence in the operative scar.
Suffocation of the surrounding skin with plastic is anecdotally effective, akin to the "duct tape" method. A layer of plastic wrap is cut slightly larger than the surface area of the wart(s), and then affixed firmly with a bandage. Care must be taken to ensure the skin does not breathe for long periods between fresh dressings, and effective results should be noticeable within 2 weeks, or else be discontinued. Despite the excess moisture of sweat, the lack of oxygen speeds the degeneration of the wart and surrounding skin; especially in combination with other treatments that gradually expose the root, such assalicylic acid.