A verruca is a wart that grows on the sole of the foot, caused by the human papillomavirus (HPV) entering through tiny breaks in the skin. Unlike warts on other parts of the body that tend to grow outward, verrucas are pushed flat and inward by the pressure of walking, which is why they can become painful. The medical term is “plantar wart,” with “plantar” simply meaning the bottom of the foot.
What Causes a Verruca
Several strains of HPV are responsible, but the most common culprits are HPV types 1, 2, 27, and 57. The strain matters more than you might expect. HPV type 1 tends to cause verrucas that are far more likely to clear up on their own, while types 2, 27, and 57 produce more stubborn lesions that resist both natural healing and treatment. In one clinical trial, 58% of HPV 1 verrucas resolved without any treatment, compared to just 7% of those caused by HPV 2, 27, or 57.
The virus thrives in warm, moist environments. You pick it up through direct skin-to-skin contact or by walking barefoot on contaminated surfaces like pool decks, communal showers, and gym changing rooms. The virus doesn’t penetrate intact skin easily. It needs a way in: a small cut, a blister, softened skin from prolonged moisture, or even a tiny abrasion you wouldn’t notice. Once inside, HPV causes skin cells to multiply rapidly, building up the tough, rough growth you see on the surface.
How to Identify a Verruca
A verruca typically appears as a small, rough, circular lump on the sole of the foot with a cauliflower-like texture. It’s usually flat or slightly raised and may have a ring of thickened skin around it. One of the most distinctive features is the presence of tiny black dots scattered across the surface. These aren’t “seeds” or dirt. They’re small blood vessels that have clotted inside the wart (thrombosed capillaries), and they’re a reliable sign you’re looking at a verruca rather than something else.
There’s also a useful visual test. The natural skin lines on the sole of your foot, the ones that look like fingerprints, will go around a verruca but not over it. With a corn or callus, those lines continue straight across the surface. This is one of the simplest ways to tell the difference at home.
Verruca vs. Corn vs. Callus
All three can feel like a painful lump underfoot, but they’re quite different. A corn is a small, cone-shaped area of hardened skin that develops from repeated pressure, often from tight shoes. It has a dense center and hurts most when you press directly on it. A callus is a broader, flatter patch of thickened, yellowish skin that forms over areas like the ball of the foot or heel from friction over time. Neither corns nor calluses have black dots or interrupt your skin lines.
A quick way to test at home: press directly down on the lump, then squeeze it from the sides. Corns tend to hurt more with direct pressure. Verrucas are typically more painful when squeezed from the sides.
Do Verrucas Go Away on Their Own?
Often, yes. This is especially true in children. A study following 364 children who had warts at age eleven found that only 7% still had them by age sixteen, a 93% natural clearance rate. A separate study of 366 schoolchildren found that half were wart-free within one year without treatment. Younger children and those of non-Caucasian ethnicity tended to clear warts faster.
Adults don’t fare quite as well. The immune response that eventually recognizes and destroys the virus-infected cells tends to be quicker and more robust in children. For adults, verrucas can persist for years, especially those caused by the more stubborn HPV strains. The practical takeaway: if your child has a verruca that isn’t causing pain, waiting it out is a reasonable approach. For adults with a persistent or painful verruca, treatment is worth considering.
Home Treatment With Salicylic Acid
The most common over-the-counter treatment is salicylic acid, which works by softening and dissolving the layers of infected skin so your immune system can better reach the virus underneath. Pharmacy products typically come in lower concentrations (around 15% to 26%), while clinical-strength preparations go up to 50%. In a randomized controlled trial, the clinical-strength 50% salicylic acid was applied once daily for up to eight weeks.
For best results at home, soak your foot in warm water for five to ten minutes to soften the skin, then gently file away the dead surface tissue with a disposable emery board or pumice stone before applying the acid. This makes it easier for the treatment to penetrate. Consistency matters: you need to apply it daily, and it often takes several weeks to see results. Keep in mind that over-the-counter concentrations are lower than what’s used in clinical studies, so patience is essential.
Professional Treatments
When home treatment doesn’t work after two or three months, several professional options exist. Cryotherapy, where liquid nitrogen is applied to freeze and destroy the wart tissue, is the most widely available clinic-based treatment. It typically requires multiple sessions spaced a few weeks apart. The freezing creates a blister beneath the wart, and as the blister heals, the dead tissue falls away. It can be uncomfortable during and after the procedure, and it doesn’t always work on the first round.
Microwave therapy is a newer alternative that uses controlled microwave energy delivered through a probe pressed against the wart. It penetrates deeper into the tissue than cryotherapy, targeting the lower layers where the virus lives. Treatments are quick (a few seconds per application) and typically require fewer sessions overall. Many patients report less downtime afterward compared to freezing.
For verrucas that resist everything else, a technique called needling can be effective. Under local anesthesia, a fine needle is used to puncture the wart repeatedly, pushing viral particles deeper into the tissue where the immune system can detect and respond to them. In one study of 41 patients, the needled wart resolved completely in 85% of cases. Even more interesting, in patients with multiple warts, 64% saw all their warts clear, including ones that weren’t directly treated. This happens because the procedure essentially alerts the immune system to the virus, triggering a body-wide response.
How Verrucas Spread and How to Prevent Them
The virus spreads through both direct contact and contaminated surfaces. Sharing towels, socks, or shoes with someone who has a verruca increases your risk, as does walking barefoot in places where the virus lingers. You can also spread verrucas to other parts of your own body, particularly if you nick the wart while shaving or pick at it.
Prevention comes down to a few habits:
- Wear flip-flops or pool shoes in communal showers, locker rooms, and around swimming pools.
- Keep feet clean and dry. Wash daily with soap, dry thoroughly between the toes, and change socks regularly.
- Cover any cuts or abrasions on your feet with a waterproof bandage before walking in shared spaces.
- Don’t share towels, socks, or shoes with others.
- Cover existing verrucas with a waterproof plaster or verruca sock when swimming or using shared facilities.
- Let shoes air out between wears to reduce moisture buildup.
Well-fitting shoes also help. Tight footwear that causes blisters or friction creates the exact kind of small skin breaks the virus needs to get in.
Who Should Avoid Self-Treatment
Most verrucas are harmless and manageable at home, but some people should see a healthcare professional rather than treating themselves. If you have diabetes, peripheral neuropathy (reduced sensation in your feet), or poor circulation, self-treatment with acids or abrasive filing carries real risks. Reduced sensation means you may not feel when you’ve damaged healthy tissue, and impaired blood flow slows healing and raises infection risk. In rare cases, what looks like a stubborn verruca in someone with diabetes can turn out to be a different type of skin lesion entirely, making accurate diagnosis important.
It’s also worth getting a professional opinion if a verruca changes color significantly, bleeds without being picked at, grows rapidly, or hasn’t responded to consistent home treatment after three months.