Plantar Warts

Plantar warts, sometimes called verrucas, are a type of wart found on the sole of the foot or the toes, most commonly in weight-bearing locations such as the heel. They are a very common type of wart, especially in children, and are caused by the human papillomavirus (HPV) – a common viral infection of the skin. HPV infections in locations other than the foot are not classed as plantar warts.

HPV is contagious, meaning plantar warts can be passed from person to person, either through direct skin-to-skin contact or indirectly through contact with a surface or object that carries the virus. People with weakened immune systems and children are more at risk of developing common warts.

In the majority of cases, plantar warts are no cause for concern and will often disappear naturally. Treatment and removal options, however, are available, particularly for cases in which the warts are causing severe pain or discomfort. 1 If you are concerned that you may have plantar warts, try using the free Ada app to carry out a symptom assessment.

Signs and symptoms of plantar warts include: 2

• Small, rough, skin-colored or white lesions on the bottom of the foot, typically around the heel or the underside of the toes
• Small black dots which are sometimes referred to as wart seeds, but are actually clotted blood vessels in or around the warts
• Hard calluses on the sole of the foot, where a plantar wart has been forced to grow inwards, below the surface of the skin
• Pain or discomfort when walking or standing, mostly in or around the affected areas

Medical attention should be sought in the following cases:

• Warts begin to bleed, change colour or cause significant pain
• Warts recur despite treatment or appear in large groups
• An individual also has diabetes, HIV/AIDS) or other immune system disorders
• Sensation is lost in the affected foot
• There is uncertainty as to whether a growth is a wart or a different kind of skin condition

If you are concerned that you may have plantar warts, try using the free Ada app to carry out a symptom assessment.

Plantar warts are caused by the human papillomavirus (HPV) – an umbrella term for a group of viruses that affect the skin. The virus causes an excess of the protein keratin to develop on the surface of the skin, resulting in warts. 3 4

HPV can cause warts anywhere on the body, however, only warts on the foot are classed as plantar warts. The virus typically enters the skin through small cuts or weak spots in the outermost layer of the skin and can take a number of weeks or months to produce visible warts.

Warts are spread from person to person, sometimes indirectly through objects or surfaces such as:

• Surfaces around swimming pools
• Floors of communal changing rooms
• Shared socks and shoes
• Shared towels

Damaged or wet skin is most susceptible to infection. Children and teenagers are more likely than adults to develop plantar warts. People with weakened immune systems as a result of other conditions are also at an increased risk of contracting HPV.

Diagnosing plantar warts will ordinarily involve a doctor or specialist examining the affected area and checking for visible signs and symptoms. In most cases, a person can themselves diagnose these warts at home, and it is rare that any further diagnostic tests will be necessary. 5 However, if the diagnosis is unclear, a doctor may order a skin biopsy. In this minimally invasive procedure, the top layer of the skin growth will be scraped off and sent to a laboratory for testing. 6

Plantar warts will, in the majority of cases, disappear without any treatment – this, however, could take months or years to happen. If the warts are persistent, painful or if they spread, treatment may be recommended to remove them.

Home remedies are available and can be effective in removal of the warts in some cases. If they prove resistant, however, doctors can recommend further treatment methods. 7

Plantar warts removal methods include:

Salicylic acid: This is a strong acid, generally applied as a gel, that gradually dissolves layers of skin from the affected area, eventually resulting in complete removal of the wart. Though it is available over the counter, prescription varieties tend to be stronger and more effective. As well as peeling away the surface of the warts, salicylic acid may also stimulate the immune system to fight the virus.

Cryotherapy: In cryotherapy, a doctor freezes the warts by applying liquid nitrogen. The process results in a blister forming around the wart that can, after around a week, be removed. Repeated sessions may be necessary.

The use of salicylic acid and cryotherapy are the most common treatment methods. If these are ineffective, however, others are available.

Trichloroacetic acid: This is another strong acid applied by a doctor after the surface of the wart has been shaved off.

Immunotherapy: This treatment method involves injecting the warts with antigens that stimulate the immune system into fighting the HPV infection. It may help prevent repeat outbreaks in those with recurring warts. 8 9 10

In extreme cases surgical removal may be necessary if the plantar warts do not respond to other methods.

Surgical methods of plantar wart removal include:

Electrosurgery: Often viewed as a last resort, this surgery involves using an electric needle to burn away the warts. This procedure can often be painful, and there is a risk of scarring.

Laser treatment: The effectiveness of laser treatment is disputed and comes with a risk of pain and scarring. It is typically carried out using a pulsed dye laser to cauterize the skin and kill skin tissue to remove the wart

As plantar warts are generally non-serious, many people attempt to treat the condition at home, before seeking professional medical attention. There are a variety of methods for doing this: 11

Salicylic acid products: A range of non-prescription salicylic acid products, including plasters, gels and rubs, are available from almost all pharmacies. They are not as strong as prescription versions, but work in the same way. It is usually necessary to apply the products a number of times

Liquid nitrogen: Non-prescription liquid nitrogen products are also available from pharmacies. They usually come in the form of a gel or liquid that can be applied to the wart.

Apple cider vinegar: One cup of apple cider vinegar can be mixed with water, then applied to the warts using a cotton ball and left for a minimum of 20 minutes. This process may need to be repeated over a number of weeks for benefits to be seen. 12

Duct tape: Although dermatologists aren’t clear on exactly why, or if, this method works, the use of duct tape is a well-known and popular method of plantar warts removal. Simply apply duct tape to the warts and change it every couple of days until the wart is gone. It is recommended that a doctor be consulted before attempting this method.

Home remedies can take a significant amount of time to yield results. If they prove ineffective, seeking professional medical advice is advised.

Plantar warts are common and can be difficult to protect against. However, taking certain preventative measures may help reduce the risk of infection: 13

• Covering the feet with shoes or sandals, for example, when using communal areas like swimming pools and locker rooms
• Washing the feet and hands regularly
• The HPV vaccine may reduce the risk of developing plantar warts, though this is not guaranteed and may be most effective when administered at a young age 14

Those who have plantar warts should make efforts to prevent the spread of the virus to other parts of the body, as well as to other people. They can: 15

• Avoid sharing towels, shoes and socks
• Cover warts with a plaster when swimming
• Wear shoes or sandals in communal areas
• Avoid scratching or unnecessarily touching warts
• Change socks daily

Q: Do plantar warts have roots or seeds?
A: There is a popular misconception that plantar warts have roots or seeds that can grow through the skin and attach to bone. The small red or black dots that have led to this idea are, in fact, clotted blood vessels, not roots. 16

Q: Can plantar warts spread to the hands and fingers?
A: The HPV that causes plantar warts can spread to the hands and fingers and cause warts. However, when found on the hands or fingers, these warts are no longer termed plantar warts, but palmar warts. To help stop the spread of the virus, avoid unnecessarily touching the affected area, and wash the hands thoroughly after any contact. Covering the wart with a plaster may also help. 17

Q: Are plantar warts contagious?
A: Yes, the HPV that causes plantar warts is contagious. It can be passed from person to person, as well as indirectly through surfaces or objects. The virus particularly thrives in warm, moist environments, meaning it is commonly contracted in swimming pools or locker rooms. 18

Q: Does duct tape really work to remove plantar warts?
A: There is no clear evidence to suggest that the application of duct tape really works to remove plantar warts. However, the method is enduringly popular and does seem to work for some people, despite the science behind this being unclear. If you are considering using this method, consult a doctor beforehand. 10

Q: Can plantar warts be cancerous?
A: In the vast majority of cases, plantar warts are harmless and pose no risk of cancer. Certain types of the HPV virus, however, can lead to some cancers. If plantar warts do not respond to treatment and continue to grow, a biopsy should be carried out to check for cancerous cells. 19