Plantar warts: Options for treating this common foot condition

Plantar warts are a common and often stubborn foot condition that can be uncomfortable and frustrating. These small, rough growths typically develop on the soles of the feet and may be painful when walking or standing.

While plantar warts are not dangerous, they can be persistent and difficult to treat. Fortunately, there are several effective treatment options, ranging from over-the-counter remedies to professional medical procedures.

What are plantar warts?

Plantar warts are noncancerous skin growths that develop on the bottom of the foot. They are caused by certain strains of the human papillomavirus (HPV), which infects the outer layer of the skin. These warts are often found on weight-bearing areas like the heels and balls of the feet, where pressure can cause them to grow inward, forming a thick, callus-like surface.

Unlike other types of warts that may appear smooth, plantar warts often have a rough texture and tiny black dots. They can vary in size and some people may have just one, while others develop clusters known as mosaic warts.

What causes plantar warts?

Plantar warts develop when the HPV virus enters the skin through tiny cuts or breaks. This virus thrives in warm, moist environments, making places like locker rooms, swimming pools, and communal showers common sources of infection.

Warts can develop at any age, but they become more frequent in school-age kids, with the highest occurrence between ages 12 and 16. Anyone can get plantar warts, but certain factors increase the risk, including:

• walking barefoot in public areas
• having a weakened immune system
• frequenting environments with warm, damp surfaces
• having a history of warts or skin conditions that cause breaks in the skin, such as eczema.

Because HPV spreads through direct or indirect contact, sharing towels, socks, or shoes with an infected person may also increase the risk of developing plantar warts.

Signs and symptoms of plantar warts

Plantar warts can sometimes be mistaken for corns or calluses, but there are a few key features that set them apart.

• Pain or tenderness. Walking or standing may cause discomfort, especially if the wart is on a weight-bearing area.
• A rough, grainy surface. The wart may have a cauliflower-like texture and feel different from the surrounding skin.
• Small black dots. These are clotted blood vessels, and are a hallmark feature of plantar warts.
• Disrupted skin patterns. Unlike normal skin, where lines and ridges continue uninterrupted, a wart can alter the natural skin pattern.

Treating and removing plantar warts

Many plantar warts go away on their own. "Plantar warts may go away on their own in the first two years, but after that they may persist," says Dr. Rebecca Gaffney, a dermatologist and instructor in dermatology at Harvard Medical School. In adults, natural resolution can take several years or more.

If the wart is painful or uncomfortable, or is spreading to other areas of your body or to others, it might be a good idea to consider treatment. Options range from home remedies to medical interventions.

Common at-home treatments include:

• Salicylic acid. Available over the counter as a liquid, gel, or medicated pads, salicylic acid gradually removes layers of the wart over time. Dr. Gaffney recommends maximizing effectiveness by "first soaking your foot in warm water and then scrubbing away the dead skin with a pumice stone before applying the treatment." Look for products containing between 17% and 40% salicylic acid.
• Duct tape method. Some people use duct tape to cover the wart for several days, then soak it and file it down before repeating the process. While evidence on its effectiveness is mixed, it may be worth trying as a low-cost option.
• Freezing kits. Over-the-counter cryotherapy treatments use freezing sprays to destroy wart tissue. These are generally less powerful than professional cryotherapy treatments but may work for smaller warts.

If at-home treatments don't work, see a determatologist, who may recommend:

• Cryotherapy. The doctor will apply liquid nitrogen to freeze and destroy the wart. Several treatments may be needed. One drawback of cryotherapy is the discomfort experienced during the procedure.
• Prescription-strength salicylic acid. Stronger formulations are available through a doctor's office.
• Cantharidin. This is a blistering agent that causes the wart to peel off. It is a good option for those who find cryotherapy too painful.
• Laser therapy. Laser treatment destroys wart tissue by targeting blood vessels.
• Injections. Warts can be injected with solutions that can kill the virus directly or can stimulate your own immune system to fight the wart.
• Surgical removal. In rare cases, warts that do not respond to other treatments may be removed surgically, but this can leave a scar.

Plantar warts can be stubborn, and it may take multiple treatments over the course of a few weeks or months to eliminate them.

How to prevent plantar warts

It's common for plantar warts to return, even after treatment. Take preventive steps to help reduce your risk.

• Wear protective footwear. Use sandals or flip-flops in public showers, locker rooms, and pool areas.
• Keep feet clean and dry. Wash feet regularly, dry completely, and change socks daily to reduce moisture buildup.
• Avoid picking at warts. This can spread the virus to other parts of the body.
• Don't share personal items. Towels, shoes, and socks can spread the virus and should not be shared. Additionally, reserve any tools used to trim or file down warts, such as nail files or pumice stones, for that purpose only. Do not use those tools on healthy skin or nails or share them with others.
• Boost immune health. A strong immune system can help your body fight off the virus that causes warts. To start, maintain a healthy diet, get enough sleep and physical activity, and manage stress. Talk to your doctor about other ways to support your immune system.