Plantar warts: treatment options, including Swift microwave therapy

What are plantar warts?

Plantar warts are noncancerous growths on the soles of the feet, caused by a common virus, human papillomavirus (HPV). The types of HPV that cause foot warts are different from the types linked to cervical and other cancers.

The virus gets in through tiny cuts or soft, damp skin, and it survives well on warm, wet surfaces such as shower floors and pool decks. Warts usually grow on the parts of the sole that take pressure, such as the heel and the ball of the foot. Your weight pushes them inward, and a layer of hard skin builds up over the top, so they can feel like standing on a stone.

Signs of a plantar wart:

• a rough, grainy bump or flat, hard patch on the sole
• tiny black dots, which are clotted blood vessels
• skin lines that go around the wart instead of through it
• pain when you walk, or when you squeeze it from the sides
• sometimes a cluster of small warts, called mosaic warts

Plantar warts are most common in older children and teenagers. You’re also more likely to get them if you walk barefoot in communal showers and pools, or if your immune system is weakened.

Plantar wart, corn or callus?

These are easy to confuse, and they’re treated differently:

If pain under the ball of your foot isn’t from a wart, our guide to ball-of-foot pain covers other causes. A podiatrist can usually tell a wart from a corn by trimming the top layer of skin, which shows the black dots and pinpoint bleeding of a wart. A growth that looks unusual, bleeds easily or keeps growing may need a small biopsy, because a few rare skin cancers can look like warts.

Do plantar warts go away on their own?

Often, yes. The immune system eventually recognizes the virus, and many warts clear without treatment within a year or two, faster in children than in adults. A small wart that doesn’t hurt can reasonably be left alone and watched.

Treatment makes sense if the wart is painful, spreading, getting bigger, or has lasted a long time, or if you have a weakened immune system.

Plantar wart treatment at home

Salicylic acid

Salicylic acid, sold as liquids, gels and medicated pads, is the best-studied treatment you can use at home. It slowly dissolves the thick, infected skin. To use it:

1. Soak the wart in warm water for about 5 minutes, then dry it.
2. Gently file off the dead skin on top with a pumice stone or emery board used only for the wart. Throw emery boards away after use so you don’t spread the virus.
3. Protect the skin around the wart with petroleum jelly, then apply the acid or a pad cut to the wart’s size.
4. Cover it with a bandage.
5. Repeat every day, as the label directs, for up to 12 weeks.

Stop if the surrounding skin becomes very sore, red or raw. Don’t use wart acids on moles, birthmarks or broken skin.

Duct tape and home freezing kits

• Duct tape. Covering the wart with duct tape has mixed evidence: an early study found it helped, but later studies found it no better than a dummy treatment. It’s low risk if your skin tolerates it.
• Home freezing kits. These get colder than ice but not nearly as cold as the liquid nitrogen doctors use, so they’re less likely to work on thick warts on the sole.

Who shouldn’t treat warts at home

Don’t use wart acids, freezing kits or other home treatments if you have diabetes, neuropathy (numb feet) or poor circulation. You may not feel damage to the skin, and a small wound on the foot can turn into a serious one. See a podiatrist instead. Check with a doctor first if you’re pregnant, have a weakened immune system, or the wart is on a young child.

Treatments a podiatrist can offer

If home treatment hasn’t worked after about 12 weeks, or the wart is painful, large or spreading, a podiatrist can talk through these options. Trimming the thick skin over the wart doesn’t cure it, but it eases pain and helps other treatments work.

Freezing (cryotherapy)

Freezing with liquid nitrogen is one of the most common in-office treatments. It destroys the top of the wart, a blister forms, and the dead tissue peels away over 1 to 2 weeks. Most warts need several sessions, and it can leave the skin a little lighter or darker. In a large UK trial of people with plantar warts, freezing and salicylic acid worked about equally well, and each cleared warts in only a minority of people within 12 weeks. That’s a reminder that stubborn warts often need patience, or a change of approach.

Swift microwave therapy

Swift is a newer device that delivers microwave energy through a small probe pressed onto the wart. Each burst heats a small area of the wart for a couple of seconds. It’s thought to work in two ways: by damaging the infected skin, and by prompting the immune system to recognize and clear the virus.

What it’s like:

• The thick skin over the wart is usually filed down first.
• Each burst lasts a couple of seconds and feels like a sharp, intense heat that fades quickly. Each wart gets a few bursts. Most people don’t need a numbing injection.
• There’s usually no blister or dressing, and most people walk normally and go back to their usual activities the same day. The spot may be tender for a day or two.
• Treatment is usually repeated about 4 weeks later, often for 2 to 4 sessions in total.

What the evidence shows: most of the published evidence comes from reports of patients treated at single clinics, without a comparison group. In one review of 85 people treated at a US podiatry practice, warts cleared in 60% of everyone who started treatment, and in most of those who completed it, after an average of about 2 to 3 sessions. A company-funded randomized trial has compared Swift with freezing, and in 2025 the FDA cleared the device for treating common and plantar warts. The maker reports less pain and fewer side effects than freezing. Independent, peer-reviewed comparisons with standard treatments are still few, so it’s fair to call Swift a promising option rather than a proven best choice.

Who it may not suit: clinics generally avoid using it on people with a pacemaker or other implanted electronic device, or near metal implants in the foot. Studies have left out people who were pregnant or had diabetes, neuropathy or a weakened immune system. Swift is only offered at some podiatry and dermatology clinics, and insurance may not cover it, so ask about suitability and cost first.

Other options for stubborn warts

• Cantharidin is a blistering liquid painted on in the office. It’s sometimes combined with other ingredients that aren’t used in pregnancy, so tell your podiatrist if you’re pregnant.
• Immunotherapy includes injecting a yeast (Candida) antigen into the wart, or painting on a substance that causes a mild allergic reaction, to get the immune system to fight the virus.
• Bleomycin injections into the wart are sometimes used for very stubborn warts. They can be painful and aren’t used in pregnancy.

What to expect from plantar wart treatment

• It takes time. Most treatments need weeks to months and more than one session.
• No treatment works for everyone. If one approach hasn’t helped after a fair trial, switching to another often does.
• Warts can come back, because some virus can stay in the nearby skin, or you can pick it up again.
• Pain usually eases as the wart shrinks, and trimming the hard skin on top can help in the meantime.

How to prevent plantar warts

• Wear sandals or shower shoes in locker rooms, communal showers and around pools.
• Keep your feet clean and dry, and change damp socks.
• Don’t pick, scratch or cut at warts, which can spread them.
• Use a separate file or pumice stone for a wart, and don’t use it on other skin.
• Cover a wart with a waterproof bandage when swimming.
• Don’t share towels, socks or shoes.

When to see a podiatrist for a plantar wart

Get seen promptly if:

• a wart or the skin around it becomes red, swollen, hot or full of pus, especially after home treatment
• you have diabetes, neuropathy or poor circulation and have any wart, sore or skin change on your foot

Book a visit if:

• the wart is painful or makes walking uncomfortable
• it’s spreading, or you have several warts
• it bleeds, changes color, grows quickly or looks unusual
• it hasn’t improved after 12 weeks of home treatment
• you’re not sure whether it’s a wart, a corn or something else
• you have a weakened immune system

Warts are common in children and usually harmless. Our guide to children’s foot health covers other common problems in growing feet. If you have diabetes, see our guide to diabetic foot check-ups and read about diabetic foot care at Evolve Health.

Next step

For a small wart that doesn’t hurt, waiting or trying salicylic acid is reasonable. If a wart is painful, spreading or not responding, a podiatrist can confirm it’s a wart and help you choose among the options, including whether microwave therapy is worth considering. You can find a podiatrist near you or see all our locations, and book online.