Warts

Warts are growths on the top layer of skin. They happen when the human papillomavirus (HPV) infects skin cells and makes them grow too fast. This creates a firm, rough bump.

Warts are usually skin-colored but can look darker or have tiny black dots inside them. Those dots are small, clotted blood vessels, not "seeds" or roots. Warts sit in the top layer of skin and do not have deep roots.

Warts are generally harmless. They can spread from person to person through touch, or from one part of your body to another. There are more than 100 types of HPV. The types that cause common skin warts are different from the types linked to cancer.

Warts are small, firm bumps with a rough or grainy surface. The look varies by type and location:

• Often skin-colored, but can look white, pink, tan, or brown.
• Tiny black dots may appear inside the wart (clotted blood vessels).
• Common warts feel rough and raised, usually on the hands and fingers.
• Warts on the soles of the feet (plantar warts) may be flat and grow inward, and can hurt when you walk or stand.
• Most warts do not itch or hurt, but some can be tender.

• Common warts: Rough, raised bumps, usually on the hands, fingers, and around the nails.
• Plantar warts: Grow on the soles of the feet. Pressure pushes them inward, so they can be flat and painful.
• Flat warts: Small, smooth, flat-topped bumps. Often appear in groups on the face, legs, or backs of the hands.
• Filiform warts: Long, thin, finger-like growths, often on the face, near the eyes, nose, or mouth.
• Periungual warts: Warts around or under the fingernails and toenails.
• Genital warts: Caused by different HPV types and spread through sexual contact. These need medical care and are a separate topic.

Warts are caused by HPV. The virus enters through tiny breaks in the skin, such as cuts, scrapes, or areas of damp, softened skin. Once inside, it makes skin cells grow quickly and form a wart.

Warts spread easily:

• Skin-to-skin contact with someone who has a wart.
• Touching a surface the virus is on, such as a locker room floor, shower, or shared towel.
• Spreading from one part of your body to another, often by scratching, picking, or shaving.

Warm, moist places help the virus spread. Not everyone who touches HPV gets a wart. Your immune system plays a big role in whether one forms.

Warts are caused by HPV, but some things raise the chance of getting one or spreading it:

• Cuts, scrapes, hangnails, or cracked skin that let the virus in
• Walking barefoot in locker rooms, pools, or public showers
• Sharing towels, razors, or nail tools
• Biting nails or picking at the skin
• Sweaty hands or feet
• A weakened immune system

A doctor can usually diagnose a wart just by looking at it. They may gently pare (trim) the surface to check for the tiny black dots that point to a wart. This also helps tell a wart apart from a corn or callus.

Most warts do not need any test. Rarely, if the diagnosis is unclear, a doctor may take a small skin sample (biopsy) to look at under a microscope.

Many warts clear on their own over months to a couple of years, so treatment is optional for harmless ones. If you want to treat a wart at home:

• Salicylic acid: The main over-the-counter option. It comes as a liquid, gel, or medicated patch. It slowly peels away the wart. Soak the area, file off dead skin, then apply it daily. It can take several weeks.
• Freezing kits: Over-the-counter freezing sprays are available, but they are usually less powerful than in-office treatment.
• Cover and file: Keeping the wart covered and gently filing it can help. Use a file or pumice you do not use anywhere else.
• Be patient and gentle: Do not cut, burn, or dig at warts yourself.

To lower the chance of spreading: do not pick at warts, wash your hands after touching them, and keep them covered.

Look for over-the-counter wart treatments that contain salicylic acid, which is the most studied at-home option. It comes in liquids, gels, and medicated pads or patches. Higher-strength salicylic acid (around 17% for most warts, and stronger for thick foot warts) tends to work better, but it takes weeks of daily use. Pair it with a file or pumice stone that you keep just for the wart and do not use anywhere else on your body.

When home care is not enough, a dermatologist has stronger options:

• Cryotherapy (freezing): Liquid nitrogen freezes the wart. Usually done over several visits.
• Cantharidin: A blistering solution applied in the office. It lifts the wart off as the blister heals.
• Immunotherapy: Medicines (such as an injected antigen or topical imiquimod) that prompt your immune system to attack the wart.
• Bleomycin injections: A medicine injected into stubborn warts.
• Stronger salicylic acid or retinoid creams: Sometimes used, especially for flat warts.

No single treatment works for everyone, and warts can need more than one round.

For warts that do not clear with creams, dermatologists often use in-office procedures. Cryotherapy (freezing with liquid nitrogen) is the most common. Other options include laser treatment (such as pulsed-dye laser to target the wart's blood vessels), electrosurgery (burning), and curettage (scraping the wart away).

See a dermatologist if a wart is painful, bleeds, or changes in color or shape; you have many warts or they keep spreading; warts are on your face or genitals; over-the-counter treatment has not worked after a few months; you have diabetes or a weakened immune system (do not treat foot warts yourself); or you are not sure the growth is really a wart.

A few things can look like a wart:

• Corns and calluses: Thickened skin from pressure, usually on the feet. They lack the tiny black dots and have a smoother surface.
• Skin tags: Soft, smooth flaps of skin, not rough like warts.
• Molluscum contagiosum: Small, smooth, dome-shaped bumps with a central dimple, caused by a different virus.
• Seborrheic keratoses: Waxy, "stuck-on" growths, more common with age.
• Skin cancer: Rarely, a growth that looks like a wart but bleeds, grows, or does not heal can be skin cancer. Get any changing growth checked.