Warts are bumps that can grow on any body part, including the feet. They are non-cancerous skin growths that may be painful but usually disappear on their own.
Plantar warts are rough bumps that grow on the feet. They usually appear on the heels — the areas of the feet that experience the most pressure.
Plantar warts result from human papillomavirus (HPV). The virus can penetrate cuts or tears on the soles of the feet. Up to 33% of children have warts, but they are less common in adults.
Like any other type of warts, plantar warts are harmless and go away with little to no treatment. However, treatments are available.
What are plantar warts?
Plantar warts usually grow on the soles of the feet, particularly at pressure points. Plantar warts are sometimes called verrucas, and they can grow quite large.
Unlike other kinds of warts, plantar warts do not grow outward. Because the soles of the feet support the body when a person is standing, pressure pushes the warts inward, which can cause pain.
Two types of plantar warts can appear on the feet:
- Myrmecial-type plantar warts: These warts develop as a result of HPV-1 infection. They appear as domed, smooth-surfaced lesions. The myrmecial type may contain black or brownish dots, which are tiny burst blood vessels. They tend to cause pain while a person is walking or standing.
- Mosaic-type plantar warts: Mosaic-type warts are clusters of plantar warts that pack tightly together. HPV-2 infection is responsible for this type of warts. They tend to be flatter and less painful than myrmecial warts.
Causes
Plantar warts result from HPV infections. Warts occur when the virus enters skin cells through cuts or injuries on the bottom of the foot. The virus makes the skin cells grow more quickly, which causes a thickened bump, or wart, to form.
HPV is very common and contagious, with hundreds of variations. However, only a few types of HPV cause plantar warts. The viruses perform best in warm, moist places such as communal areas near swimming pools, and they are most likely to infect moist or injured skin.
If a person scratches or picks a wart, they may transfer the virus elsewhere, such as under the fingernail. This might cause more warts to grow, separately from the original infection site.
Treatment
Warts often go away without treatment, although this can take several weeks to years. The immune system can clear the virus over time, so the warts disappear. People with compromised immune systems may find it more difficult to get rid of warts.
Doctors have many treatment options for warts, including:
- cryotherapy, or freezing medication
- cantharidin, which causes a blister under the wart that cuts off its blood supply
- electrosurgery and curettage, which involves scraping and burning the wart
- excision, which involves cutting off the wart
For stubborn warts, a dermatologist may recommend laser treatment or immunotherapy. People can also try various home remedies to treat warts, such as salicylic acid products or the duct tape method.
