Plantar wart
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A plantar wart is a wart occurring on the bottom of the foot or toes.<ref name=AO2017>Template:Cite web</ref> Its color is typically similar to that of the skin.<ref name=V2016/> Small black dots often occur on the surface.<ref name=AO2017/> One or more may occur in an area.<ref name=V2016/> They may result in pain with pressure such that walking is difficult.<ref name=V2016/>
They are caused by the human papillomavirus (HPV).<ref name=V2016>Template:Cite journal</ref> A break in the skin is required for infection to occur.<ref name=V2016/> Risk factors include use of communal showers, having had prior warts, and poor immune function.<ref name=V2016/><ref name=Fer2018>Template:Cite book</ref> Diagnosis is typically based on symptoms.<ref name=Fer2018/>
Treatment is only needed if it is causing symptoms.<ref name=Fer2018/> This may include salicylic acid, cryotherapy, chemo-based fluorouracil or bleomycin, and surgical removal.<ref name=V2016/> The skin atop the lesion should generally be removed before treatment.<ref name=V2016/> In about a third to two-thirds of cases, they go away without specific treatment, but this may take a few years.<ref name=V2016/> Plantar warts are common.<ref name=AO2017/> Children and young adults are most often affected.<ref name=Fer2018/>
Signs and symptoms
Their colors are typically similar to that of the nearby skin.<ref name=V2016/> Small, black dots may occur on their surfaces.<ref name=AO2017/> One or more may occur in an area.<ref name=V2016/> They may result in pain with pressure, such that walking may be difficult.<ref name=V2016/>
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A plantar wart: striae (fingerprints) go around the lesion.
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Mosaic wart cluster
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Young plantar warts
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30-year-old plantar wart
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Deep, painful plantar warts
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Deep plantar wart on heel
Cause
Plantar warts are benign epithelial tumors generally caused by infection by human papillomavirus types 1, 2, 4, 60, or 63,<ref name="emed_hpv">Template:EMedicine</ref> but also by types 57,<ref name="egawa">Template:Cite journal</ref> 65,<ref name="compendium1994">Template:Cite web</ref> 66,<ref name="davis">Template:Cite journal</ref> and 156.<ref name="chouhy2013">Template:Cite journal</ref> These types are classified as clinical (visible symptoms). The virus attacks compromised skin through direct contact, possibly entering through tiny cuts and abrasions in the stratum 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.<ref name="emed_plantar">Template:EMedicine</ref><ref name="hipusa"/>
Warts may spread through autoinoculation, by infecting nearby skin, or by contaminated walking surfaces. They may fuse or develop into clusters called mosaic warts.<ref name="emed_hpv"/>
Diagnosis
A plantar wart is a small lesion that appears on the surface of the skin and typically resembles a cauliflower, with tiny black petechiae (tiny hemorrhages under the skin) in the center. Pinpoint bleeding may occur when these are scratched. Plantar warts occur on the soles of the feet and toes. They may be painful when standing or walking.Template:Cn
Plantar warts are often similar to calluses or corns, but can be differentiated by close observation of skin striations. Feet are covered in friction ridges, which are akin to fingerprints of the feet. Friction ridges are disrupted by plantar warts; if the lesion is not a plantar wart, 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 corns (which tend to be painful on direct pressure instead).Template:Cn
Prevention
HPV is spread by direct and indirect contact from an infected host. Avoiding direct contact with contaminated surfaces such as communal changing rooms and shower floors and benches, avoiding sharing shoes and socks, and avoiding contact with warts on other parts of the body and on the bodies of others may help reduce the spread of infection. Infection is less common among adults than children.<ref name="hipusa">Template:Cite web</ref>
As all warts are contagious, precautions should be taken to avoid spreading them. Recommendations include:
- Cover them with an adhesive bandage while swimming
- Wear latex swimming socks
- Wear flip-flops when using communal showers
- Do not share towels.<ref name="nhs">Template:Cite web</ref>
Plantar warts are not prevented by inoculation with HPV vaccines because the warts are caused by different strains of HPV. Gardasil protects against strains 6, 11, 16, and 18, and Cervarix protects against 16 and 18, whereas plantar warts are caused by strains 1, 2, 4, and 63.{{ safesubst:#invoke:Unsubst||date=__DATE__ |$B= Template:Fix }}
Treatment
| First-line therapy | Over-the-counter salicylic acid |
| Second-line therapy | Prescribed 60% salicylic acid, intralesional immunotherapy |
| Third-line therapy | Fluorouracil cream, cryotherapy, laser therapy |
| Fourth-line therapy | Bleomycin injection, surgical excision |
A number of treatments have been found to be effective.<ref name="bacelieri">Template:Cite journal</ref> A 2012 review of different treatments for skin warts in otherwise healthy people concluded modest benefit from salicylic acid, and cryotherapy appears similar to salicylic acid.<ref>Template:Cite journal</ref>
Medications
Salicylic acid, the treatment of warts by keratolysis, involves the peeling away of dead surface skin cells with keratolytic chemicals such as salicylic acid or trichloroacetic acid. These are available in over-the-counter products, but in higher concentrations may need to be prescribed by a physician. A 12-week daily treatment with salicylic acid has been shown to lead to a complete clearance of warts in 10–15% of the cases.<ref>Template:Cite journal</ref>
Formic acid, topical, is a common treatment for plantar warts, which works by being applied over time, causing the body to reject the wart.<ref>Template:Cite journal</ref>
Fluorouracil cream, a chemotherapy agent sometimes used to treat skin cancer, can be used on particularly resistant warts, by blocking viral DNA and RNA production and repair.<ref name="fluorouracil" />
Bleomycin, a more potent chemotherapy drug, can be injected into deep warts, destroying the viral DNA or RNA. Bleomycin is notably not US FDA approved for this purpose. Possible side effects include necrosis of the digits, nail loss, and Raynaud syndrome. The usual treatment is one or two injections.<ref>Template:Cite journal</ref><ref>Champion, R. H., et al. (1998). Rook's Textbook of Dermatology. Blackwell Science, p. 1044, Template:ISBN</ref>
Immunotherapy, as intralesional injection of antigens (mumps, candida or trichophytin antigens USP), is a wart treatment that may trigger a host immune response to the wart virus, resulting in wart resolution. It is now recommended as a second-line therapy.<ref>Template:Cite journal</ref>
Procedures
Liquid nitrogen and similar cryosurgery methods are common surgical treatments, which act by freezing the external cell structure of the warts, destroying the live tissue.Template:Cn
Electrodesiccation and surgical excision may produce scarring.Template:Cn
Laser surgery is generally a last resort treatment, as it is expensive and painful, but may be necessary for large, hard-to-cure warts.<ref>"Laser Surgery for Warts", webmd.com</ref>
Cauterization may be effective as a prolonged treatment. As a short-term treatment, cauterization of the base with anesthetic can be effective, but this method risks scarring or keloids. Subsequent surgical removal, if necessary, also risks keloids and/or recurrence in the operative scar.<ref name="kunnamo">Template:Cite book</ref>
Duct tape occlusion therapy involves placing a piece of duct tape over the wart. The mechanism of action of this technique still remains unknown. Despite several trials, evidence for the efficacy of duct tape therapy is inconclusive.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref> 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.<ref>Template:Cite journal</ref> Template:-
References
External links
- Plantar warts at the Mayo Clinic website
- Warts at Merck Manual
Template:Viral cutaneous conditions Template:Human papillomavirus