If you’re staring at a bump on your skin and wondering whether it’s a wart, there are a few reliable ways to tell. Warts have distinct visual signatures that set them apart from other skin growths, and knowing what to look for can save you a trip to the doctor or, in some cases, tell you it’s time to make one.
What a Wart Looks Like
A common wart typically appears as a round or oval, rough bump that’s skin-colored or slightly grayish. The surface feels hard and raised, almost like a tiny dome of compacted skin. The single most telling feature is the presence of small black dots scattered across the surface. These are often called “wart seeds,” but they’re actually tiny blood vessels that have clotted inside the wart. If you see those dark specks in a rough, firm bump, you’re almost certainly looking at a wart.
Another reliable test you can do at home: look at your skin lines. Natural fingerprint-like ridges on your hands and feet flow in smooth, continuous patterns. A wart interrupts those lines. The skin markings will curve around or stop at the edges of the growth rather than passing through it. A callus, by contrast, preserves those lines.
Types of Warts and Where They Appear
Not all warts look the same. The type you have depends largely on where it grows.
- Common warts show up most often on hands, knuckles, elbows, and knees. They’re rough, raised, and round.
- Plantar warts grow on the soles of your feet and get pushed flat from the pressure of walking. They look like rough, thickened patches of skin and can feel like stepping on a pebble.
- Flat warts are smaller, smoother, and have a flat top rather than a dome shape. They tend to appear on the face or on skin you shave, sometimes in clusters of dozens.
- Filiform warts look distinctly different from the rest. Instead of being hard and round, they have thin, thread-like projections sticking out, almost like tiny tentacles. These usually grow on the face, especially near the eyelids, lips, or nose.
- Genital warts can appear as a single bump or in clusters that resemble cauliflower. They’re soft rather than hard and require different treatment than skin warts.
What Causes Warts
Every wart is caused by the human papillomavirus (HPV), but not the same strains you hear about in connection with cervical cancer. Common skin warts are driven by HPV types 2 and 4, while plantar warts are most often caused by HPV type 1. There are over 100 strains of HPV, and the ones responsible for ordinary warts on your hands and feet are low-risk and not associated with cancer.
The virus enters through tiny breaks in the skin, sometimes so small you can’t see them. A hangnail, a scrape from a razor, cracked cuticles, or the softened skin on wet feet at a public pool are all common entry points. Once inside, the virus causes skin cells to multiply rapidly, building the hard, raised lump you see on the surface. The incubation period varies, but warts generally take a few months to become visible after exposure. You may never pinpoint where you picked up the virus.
Warts spread through direct skin-to-skin contact or by touching contaminated surfaces like shared towels, shower floors, or gym equipment. You can also spread them to other parts of your own body, especially by picking at a wart and then touching another area.
Growths That Look Like Warts but Aren’t
Several other skin conditions can fool you into thinking you have a wart.
Seborrheic keratoses are one of the most common impostors. These are noncancerous growths that appear in middle age and beyond. They look like waxy, tan-to-brown spots that seem stuck onto the skin’s surface rather than growing out of it. The key difference: seborrheic keratoses have a smooth, waxy texture and often contain small, round keratin plugs visible on close inspection. Warts, by contrast, are rough, irregularly surfaced, and more likely to be skin-colored or grayish with those characteristic black dots.
Corns and calluses are another common mix-up, especially on the feet. Both are thickened areas of skin caused by friction, not a virus. The skin-line test mentioned above is the fastest way to distinguish them. Calluses preserve your natural skin ridges; warts disrupt them. Corns also tend to have a hard, defined center of pressure rather than the scattered dark specks of a plantar wart.
Skin tags are soft, floppy pieces of skin that hang from a thin stalk. They’re painless, smooth, and skin-colored. Unlike warts, they’re not rough or hard and they don’t have black dots.
When a “Wart” Could Be Something Serious
Rarely, a growth that looks like a wart can turn out to be a type of skin cancer called squamous cell carcinoma. Published case reports have documented lesions initially diagnosed as warts that were later found to be cancerous after they failed to respond to standard treatments. A few warning signs should prompt closer evaluation: the bump is growing rapidly in height or width, the center ulcerates or bleeds without being picked at, or the texture doesn’t quite match what a typical wart looks like.
A wart that persists despite multiple rounds of treatment over 18 months or longer also warrants a closer look. In those cases, a dermatologist may recommend a biopsy, a quick procedure where a small sample of tissue is examined under a microscope to confirm what the growth actually is.
How Warts Are Treated
Many warts eventually clear on their own as your immune system recognizes and fights the virus, but this can take months or even years. If you’d rather not wait, over-the-counter salicylic acid is the most accessible first-line treatment. It works by softening and dissolving the layers of the wart over several weeks of daily application. In clinical trials, salicylic acid cleared warts in about 73% of patients compared to 48% in those using a placebo, a meaningful advantage.
Freezing (cryotherapy), done in a doctor’s office, is the other common approach. A large randomized trial comparing the two methods for plantar warts found no significant difference in effectiveness: both cleared about 14% of plantar warts at 12 weeks and roughly a third by six months. Plantar warts are notoriously stubborn. Warts on hands and other locations tend to respond better to both treatments.
For either method, patience matters. You’re not burning off a single growth so much as helping your immune system catch up to a virus that’s been hiding in your skin cells. Multiple treatment sessions are normal, and recurrence is common because the underlying virus can linger even after the visible wart is gone.
If you have diabetes or a weakened immune system, skip the at-home treatments and see a dermatologist directly. Impaired circulation or immune function changes both the risks of self-treatment and the likelihood that the wart will resolve without professional help.
How to Stop Warts From Spreading
Once you’ve confirmed you have a wart, a few habits can keep it from multiplying or passing to others. Avoid picking, scratching, or biting at the wart, since this is the fastest way to spread the virus to new sites on your own skin. Cover plantar warts with a bandage or waterproof tape before walking barefoot, and wear flip-flops in shared showers or pool areas. Don’t share razors, towels, or nail clippers with others. If you shave over an area with flat warts, the razor can drag the virus across surrounding skin and trigger a new crop of growths within weeks.