A wart is a small, rough skin growth caused by human papillomavirus (HPV). The virus infects the top layer of skin, usually through a tiny cut or scratch, and triggers cells to multiply rapidly into a firm, raised bump. Warts are extremely common, particularly in children, and while they’re usually harmless, they can be stubborn to get rid of.
How HPV Creates a Wart
Your skin’s outer layer is made of cells called keratinocytes. Normally, as these cells mature, they stop dividing and eventually shed. HPV disrupts that process. Once the virus enters through broken skin, it produces proteins that essentially trick mature skin cells into continuing to grow and divide when they should have stopped. One key viral protein disables your cells’ built-in brakes on growth (a tumor suppressor called pRB), while another overrides the signals that tell cells to stop multiplying during normal skin development.
The result is a localized pile-up of excess skin cells, which forms the visible bump you recognize as a wart. The virus doesn’t travel through your bloodstream. It stays in the skin, which is why warts remain localized growths rather than a whole-body illness. Different strains of HPV target different areas: types 1, 2, 4, 27, and 57 cause the warts you typically find on hands and feet, while types 3 and 10 cause flat warts on the face and neck.
Types of Warts and What They Look Like
Common Warts
These are the most recognizable type. They appear as firm, raised bumps with an irregular, rough surface, ranging from 1 mm to several centimeters across. They show up most often on the hands and fingers. A telltale sign is tiny black dots scattered across the surface, which are small clotted blood vessels. When they form near the lips or eyelids, they tend to be thin and elongated rather than round.
Plantar Warts
Plantar warts grow on the soles of your feet. Because body weight presses them inward, they often look flat and are easily mistaken for a callus. The key difference is that plantar warts are painful when you squeeze them from the sides, while calluses hurt more with direct downward pressure. They can also have those characteristic black pinpoints that calluses lack.
Flat Warts
Flat warts are smooth, flesh-colored bumps between 1 and 7 mm across. They typically appear on the face, neck, hands, or wrists. What makes them distinct is their sheer number: you can develop dozens or even hundreds at once, often in clusters or lines where the skin was scratched.
Other Varieties
Filiform warts are long, narrow projections that grow quickly around the eyes, mouth, and nose. Butcher’s warts have a cauliflower-like appearance and tend to be large; they’re named for their association with people who handle raw meat. Cystic warts appear smooth and grow on weight-bearing surfaces like the sole of the foot.
How Warts Spread
Warts are contagious through both direct and indirect contact. Touching someone else’s wart or sharing items like towels, razors, and nail clippers can transmit the virus. HPV enters through cracked or broken skin much more easily than through intact skin, which is why people who bite their nails or pick at hangnails are more prone to warts on their fingers.
You can also spread warts to other parts of your own body. Shaving over a wart, for example, can carry the virus along the razor’s path. Warm, moist environments like public pool decks and locker room floors are common transmission sites for plantar warts, which is why wearing flip-flops in those areas helps reduce your risk. The incubation period varies widely, so a wart may not appear until months after the initial exposure.
Warts vs. Corns, Calluses, and Other Growths
Warts and corns can look similar since both are small, rough, and sometimes painful. The clearest visual difference is texture: warts have a grainy, fleshy appearance with black pinpoints, while corns look like a raised, hard bump surrounded by dry, flaky skin. Corns also develop strictly from repeated friction (tight shoes, for instance), so they appear only at pressure points, whereas warts can show up anywhere on the body.
A growth that looks like a wart but doesn’t heal within about two months, bleeds easily, or has an irregular border deserves a closer look. Squamous cell carcinoma, a type of skin cancer, can sometimes resemble a wart. Signs that set it apart include a flat sore with a scaly crust, a nodule that looks pink, red, or brown, or any new sore forming on an old scar.
Do Warts Go Away on Their Own?
Many warts do eventually clear without treatment as your immune system recognizes and fights off the virus. In children, this happens more reliably. The timeline is unpredictable, though. Some warts disappear within months, while others persist for years. A clinical trial found that even with no treatment at all, about 16% of warts cleared within 13 weeks. That’s encouraging if you’re patient, but it also means the majority stick around for a while.
Treatment Options and How Well They Work
The two most widely used treatments are over-the-counter salicylic acid and professional cryotherapy (freezing with liquid nitrogen). Salicylic acid works by softening and dissolving the excess skin layer by layer. It comes in patches, liquids, and gels, and you apply it daily after soaking and filing down the wart. It requires weeks of consistent use.
Cryotherapy involves a healthcare provider applying liquid nitrogen to freeze the wart, which destroys the infected tissue. It typically requires multiple sessions spaced two to three weeks apart. In a randomized trial, cryotherapy cured 49% of common warts within 13 weeks, compared to 15% for salicylic acid and 8% for no treatment at all. That makes cryotherapy a significantly better option for common warts on the hands and fingers.
Plantar warts are a different story. The same trial found no meaningful difference in cure rates between cryotherapy, salicylic acid, and simply waiting. Plantar warts sit deeper in the skin due to the pressure of walking, making them harder to treat regardless of the method. For these, the convenience of at-home salicylic acid treatment may be the most practical starting point.
For warts that resist standard treatment, providers may turn to stronger options like prescription-strength topical treatments, laser therapy, or minor surgical removal. Recurrence is common with any method because treatments destroy the visible wart but don’t always eliminate every trace of the virus in surrounding skin cells.
Reducing Your Risk
Since HPV thrives in warm, moist conditions and enters through damaged skin, a few practical habits lower your chances of picking up or spreading warts. Avoid sharing towels, razors, nail clippers, or socks with others. Keep cuts and scrapes covered. Wear flip-flops in communal showers and around pools. If you already have a wart, try not to pick at it or shave over it, as both can spread the virus to new areas. Keeping skin moisturized and intact is one of the simplest ways to reduce the entry points HPV needs.