Plantar warts are small growths that usually appear on the heels or other weight-bearing areas of your feet. This pressure may also cause plantar warts to grow inward beneath a hard, thick layer of skin (callus).
Plantar warts are caused by HPV. The virus enters your body through tiny cuts, breaks or other weak spots on the bottom of your feet.
Most plantar warts aren’t a serious health concern and usually go away without treatment eventually. You may want to try self-care treatments or see your doctor to have the warts removed.
Plantar warts are caused by an infection with HPV in the outer layer of skin on the soles of your feet. They develop when the virus enters your body through tiny cuts, breaks or other weak spots on the bottoms of your feet.
HPV is very common, and more than 100 kinds of the virus exist. But only a few of them cause warts on the feet. Other types of HPV are more likely to cause warts on other areas of your skin or on mucous membranes.
Transmission of the virus
Each person’s immune system responds differently to HPV. Not everyone who comes in contact with it develops warts. Even people in the same family react to the virus differently.
The HPV strains that cause plantar warts aren’t highly contagious. So the virus isn’t easily transmitted by direct contact from one person to another. But it thrives in warm, moist environments. Consequently, you may contract the virus by walking barefoot around swimming pools or locker rooms. If the virus spreads from the first site of infection, more warts may appear.
Anyone can develop plantar warts, but this type of wart is more likely to affect:
- Children and teenagers
- People with weakened immune systems
- People who have had plantar warts before
- People who walk barefoot where exposure to a wart-causing virus is common, such as locker rooms
Plantar wart signs and symptoms include:
- A small, fleshy, rough, grainy growth (lesion) on the bottom of your foot, usually the base of the toes and forefoot or the heel
- Hard, thickened skin (callus) over a well-defined “spot” on the skin, where a wart has grown inward
- Black pinpoints, which are commonly called wart seeds but are actually small, clotted blood vessels
- A lesion that interrupts the normal lines and ridges in the skin of your foot
- Pain or tenderness when walking or standing
In most cases, your doctor can diagnose a plantar wart with one or more of these techniques:
- Examining the lesion
- Paring the lesion with a scalpel and checking for signs of dark, pinpoint dots — tiny clotted blood vessels
- Removing a small section of the lesion (shave biopsy) and sending it to a laboratory for analysis
Most plantar warts are harmless and go away without treatment, though it may take a year or two. If your warts are painful or spreading, you may want to try treating them with over-the-counter (nonprescription) medications or home remedies. You may need many repeated treatments before the warts go away, and they may return later.
If your self-care approaches haven’t helped, talk with your doctor about these treatments:
- Stronger peeling medicine (salicylic acid). Prescription-strength wart medications with salicylic acid work by removing layers of a wart a little bit at a time. They may also stimulate your immune system’s ability to fight the wart.
Your doctor will likely suggest you apply the medicine regularly at home, followed by occasional office visits.
- Freezing medicine (cryotherapy). Cryotherapy done at a doctor’s office involves applying liquid nitrogen to the wart, either with a spray or a cotton swab. This method can be painful, so your doctor may numb the area first.
The chemical causes a blister to form around your wart, and the dead tissue sloughs off within a week or so. Cryotherapy may also stimulate your immune system to fight viral warts. You may need to return to the doctor’s office for repeat treatments every two to four weeks until the wart disappears.
Some studies suggest that cryotherapy combined with salicylic acid treatment is more effective than just cryotherapy, but further study is needed.
Surgical or other procedures
If salicylic acid and freezing medicine don’t work, your doctor may recommend one or more of the following treatments:
- Other acids. Your doctor shaves the surface of the wart and applies trichloroacetic acid with a wooden toothpick. You’ll need to return to the doctor’s office for repeat treatments every week or so. Side effects include burning and stinging. Between visits, you may be asked to apply salicylic acid to the wart.
- Immune therapy. This method uses medications or solutions to stimulate your immune system to fight viral warts. Your doctor may inject your warts with a foreign substance (antigen) or apply a solution or cream to the warts.
- Minor surgery. Your doctor cuts away the wart or destroys it by using an electric needle (electrodesiccation and curettage). This procedure can be painful, so your doctor will numb your skin first. Because surgery has a risk of scarring, this method usually isn’t used to treat plantar warts unless other treatments have failed.
- Laser treatment. Pulsed-dye laser treatment burns closed (cauterizes) tiny blood vessels. The infected tissue eventually dies, and the wart falls off. This method requires repeat treatments every three to four weeks. The evidence for the effectiveness of this method is limited, and it can cause pain and potentially scarring.
- Vaccine. HPV vaccine has been used with success to treat warts even though this vaccine is not specifically targeted toward the wart virus that causes the majority of plantar warts.