Plantar warts are a type of wart that develops on the soles of your feet. They’re quite annoying at first, and may even become painful if they grow large. The wart develops in the outer layer of the skin and is typically covered with a layer of callus tissue. Sometimes small black dots are visible. These are blood vessels that grow within the wart. Over time, the wart can grow and other warts can emerge that sometime coalesce into a larger cluster called a mosaic wart. Although warts are generally harmless, they can be quite painful when present on weight-bearing areas of the foot. Although most plantar warts will go away on their own after a few years, it’s possible to remove them through self-care or with a doctor’s help.
Most warts are fairly harmless. They’re skin growths caused by a strain of the human papillomavirus (HPV); however, plantar warts aren’t the same as genital warts. Instead, this virus settles into the weight-bearing pads of your feet, which causes a wart. More than anything, plantar warts are a not-so-pretty feature that can cause embarrassment and self-consciousness.
Types of Plantar Warts
There are two types of plantar warts:
- A solitary wart is a single wart. It often increases in size and may eventually multiply, forming additional satellite warts.
- Mosaic warts are a cluster of several small warts growing closely together in one area. Mosaic warts are more difficult to treat than solitary warts.
Plantar Warts risk factors
Anyone can develop plantar warts, but this type of wart is more likely to affect:
- Children and teenagers
- Having a weakened immune system
- People who walk barefoot where exposure to a wart-causing virus is common, such as locker rooms
- Repeated HPV exposure. For example, walking barefoot in public locker rooms and common public areas.
- In some cases, the virus can be transmitted to the feet from other areas of the body. This is called remote location seeding.
Causes of Plantar Warts
- You acquire warts through direct contact with the human papillomavirus (HPV). There are more than 100 types of HPV. Some types of HPV tend to cause warts on your hands, fingers or near your finger nails. Others tend to cause warts on your feet.
- The virus that causes plantar warts isn’t highly contagious, but it thrives in warm, moist environments, such as shower floors, locker rooms and public swimming areas. So you may contact the virus by walking barefoot in public places.
- Like other infectious diseases, HPV may also pass from person to person. If you have a plantar wart, you can even spread the virus to other places on your own foot by touching or scratching. The virus can also spread by contact with skin shed from a wart.
- Each person’s immune system responds to warts differently, so not everyone who comes in contact with HPV develops warts.
Plantar Warts Symptoms
Plantar warts are flesh colored growths or lesions on the soles of the feet. They tend to grow on areas of the sole that bear weight. This pressure can cause the wart to grow inward and appear flat. Flat wart lesions may only be noticeable because they interrupt the normal print lines on the bottom of the foot. Plantar warts can also be rough or look grainy.
Common symptoms of plantar warts are:
- Black dots, which are small clots that form as the wart grows deeper. People commonly call these dots wart seeds.
- Feeling like something is in your shoe
- Pain or tenderness, especially when walking or standing. You may also feel pain when you squeeze the wart.
- Thickened, hard skin over the wart, which looks like a callus. However, a callus will not be painful when you squeeze it.
- If you aren’t sure whether a lesion is a wart or not, see your doctor for a diagnosis.
Plantar Warts Complications
Plantar warts do not pose a serious health threat. When plantar warts cause pain, you may alter your normal posture or gait perhaps without realizing it. Eventually, this change in how you stand, walk or run can cause muscle or joint discomfort. This, in turn, can end up causing joint and muscle pain or discomfort. See your doctor if warts are causing pain that interferes with your ability to walk or stand normally.
Diagnosis and test
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
Treatment and medications
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 (non-prescription) 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.
Lifestyle and home remedies
Many people have removed warts with these self-care tips:
Peeling medicine (salicylic acid): Nonprescription wart removal products are available as a patch or liquid. Usually, you’re instructed to wash the site, soak it in warm water, and gently remove the top layer of softened skin with a pumice stone or emery board. Then after the skin has dried, you apply the solution or patch. Patches are usually changed every 24 to 48 hours. Liquid applications are generally used daily. You may need repeated applications on a regular basis over several weeks to months to see results.
Freezing medicine (cryotherapy): Nonprescription medicines that freeze the wart include Compound W Freeze Off and Dr. Scholl’s Freeze Away. The Food and Drug Administration cautions that some wart removers are flammable and shouldn’t be used around fire, flame, heat sources (such as curling irons) and lit cigarettes.
Duct tape: Using duct tape to remove warts is a harmless but unproven approach. To try it, cover the wart with silver duct tape, changing it every few days. Between applications, soak the wart and gently remove dead tissue with a pumice stone or emery board. Then leave the wart open to the air to dry for a few hours before covering it with tape again.
Prevention of Plantar Warts
Plantar warts are common and can be difficult to protect against. However, taking certain preventative measures may help reduce the risk of infection:
- 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
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:
- 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