What are warts?

Warts are raised bumps on your skin caused by the human papillomavirus (HPV). Warts have plagued humans for thousands of years — they have been discovered on a 3,000-year-old mummy and were mentioned by Shakespeare.

Although warts generally aren’t dangerous, they can be uncomfortable, potentially embarrassing, and contagious. They can also be painful. However, warts can be treated, either at home or by a medical professional.

There are five major types of warts. Each type appears on a different part of the body and has a distinct appearance.

Common warts

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Common warts can develop on the palm of the hand. Goldsithney/Shutterstock

Common wartsusually grow on the backs of your fingers and toes and on the knees. But they can appear elsewhere.

They can have a rough, thick, grainy appearance and a rounded top. They may appear cauliflower-like. Common warts are often grayer than the surrounding skin.

They can range in size from 1 millimeter (mm) to 1 centimeter (cm) or larger, and can occur alone or in groups.

These warts are usually not serious or painful and can go away on their own.

Signs and symptoms of common warts can include:

  • small bumps that can be hard, rough, and grainy
  • flesh-colored bumps with small black spots of clotted blood vessels
  • ability to spread to other areas through direct contact

Plantar warts

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Plantar warts occur on the sole of the foot. Dermatology11/Shuttertsock

Plantar warts grow on the soles of the feet. Unlike other warts, plantar warts grow into your skin, not out of it.

You can tell you have a plantar wart if you notice what appears to be a small hole in the bottom of your foot that is surrounded by hardened skin. Plantar warts can make walking uncomfortable.

There are two types of plantar warts that can appear on the sole of the foot.

Myrmecial-type plantar warts

These warts are caused by HPV type 1. Signs and symptoms can include:

  • deep, tender warts that grow inward due to standing or walking
  • pain with direct pressure
  • can feel like you are stepping on pebbles
  • yellowish skin that appears callus-like
  • can have black dots

Mosaic-type plantar warts

These warts are caused by HPV type 2. Signs and symptoms can include:

  • small surface-level warts
  • a mosaic pattern of multiple warts appearing in clusters
  • less painful than myrmecial-type plantar warts

Flat warts

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Flat warts can develop on fingers. Ajazqureshi221/Shutterstock

Flat warts, also known as juvenile warts, usually grow on the face, thighs, or arms. They are often caused by HPV types 3, 10, and 28.

They are small and not immediately noticeable. Flat warts have a flat top, as if they’ve been scraped. They can be flesh-colored, pink, brownish, or slightly yellow. They often grow in large groups of 20 to 200.

Flat warts are not typically painful and tend to appear in areas where there is a cut or break in your skin, such as from shaving your face or legs. They are also common in children and can be spread through direct contact.

Signs and symptoms of flat warts can include:

  • small flat, round, or oval marks on the skin
  • flesh-colored marks
  • usually not painful

Filiform warts

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Filiform warts can occur on the eyelid. Image credit: Schweintechnik, 2008.

Filiform warts grow around your mouth or nose and sometimes on your neck or under your chin. They are contagious and can also spread to other parts of your body.

Filiform warts are small and shaped like a tiny flap or tag of skin. They can project off of your skin in thin, finger-like strands.

Filiform warts are the same color as your skin. They are typically painless unless they occur in a sensitive area like a fold in your skin.

Signs and symptoms of filiform warts can include:

  • small growth that extends off of the skin
  • flesh-colored flap
  • quick growth
  • usually not painful

Periungual warts

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Periungual warts occur around the fingernails or toenails. Image credit: Med Oral Patol Oral Cir Bucal, 2019.

Periungual warts grow under and around the toenails and fingernails. They can be painful and affect nail growth.

They start small — about the size of a pinprick — but can grow larger and spread to other areas through direct contact. They may be rough to the touch and have a cauliflower-like appearance.

Signs and symptoms of periungual warts can include:

  • rough growth around or under the nail
  • painful when size increases
  • split skin around nail
  • appearance of nail and cuticle may be affected

Important information about genital warts

There are more than 100 types of HPV, the virus that causes warts. Almost all types of HPV cause relatively harmless warts that appear on your hands or feet.

However, there are a few strains of HPV that cause warts on, in, and around your genitals. These warts are called “genital warts.” If you have a cervix, genital warts can eventually lead to cervical cancer, a potentially fatal disease.

If you think you have genital warts or think you have been exposed to them, you should see a doctor right away.

You should see a doctor if:

  • You have warts on your face or another sensitive part of your body (e.g., genitals, mouth, nostrils).
  • You notice bleeding or signs of infection, such as pus or scabbing, around a wart.
  • The wart is painful.
  • The color of the wart changes.
  • You have warts and diabetes or an immune deficiency, such as HIV or AIDS.

At-home treatment

Although warts usually go away on their own, they may be embarrassing or uncomfortable, so you may want to try treating them at home. Many warts respond well to treatments available at the drugstore.

Some things to remember include:

  • You can spread warts to other parts of your body, and they are contagious to others. If a treatment requires that you rub the wart with a fingernail file or a pumice stone, don’t use that tool on any other part of your body, and don’t allow anyone else to use it.
  • Don’t try to treat warts on your feet if you have diabetes. See your doctor. Diabetes can cause loss of sensation in your feet, so you can easily injure yourself without realizing it.
  • Don’t try to remove warts on your face or another sensitive part of your body (such as your genitals, mouth, or nostrils) with at-home treatments.

Freezing treatments

Some over-the-counter treatments spray concentrated cold air (a mixture of dimethyl ether and propane) onto your wart. This kills the skin and allows you to scrape away the surface of the wart.

These treatments are a good choice if you want to try to remove a wart quickly, but they aren’t strong enough to remove all warts.

Treatments and patches containing salicylic acid

You must use these products every day, often for a few weeks. They’ll work best if you soak the wart in water for about 15 minutes before you apply the treatment and follow the directions on the package.

Duct tape

Some people have had success treating warts with duct tape. The process involves:

  1. covering the wart with a small piece of duct tape for several days
  2. soaking the wart
  3. rubbing the wart to remove the dead skin

This approach can take several rounds of treatments to work. However, according to the American Academy of Dermatology (AAD), research conflicts on whether this approach is effective.

What can my doctor do about warts?

If your wart doesn’t respond well to at-home treatments, your doctor may be able to help. Remember, always see a doctor if you have diabetes and have warts on your feet.

Liquid nitrogen

Your doctor may freeze your wart with liquid nitrogen. This can be a bit painful but usually works well. More than one treatment may be required.

Freezing causes a blister to form under and around your wart. This lifts the wart away from the skin within about a week.

Surgery

Surgery is usually only considered if a wart hasn’t responded to other treatments. Your doctor can cut away your wart with a surgical knife or burn it with electricity. You’ll need to receive a shot of anesthetic first, and these shots can be painful. Surgery may also cause scarring.

There are ways to prevent warts or keep them from spreading to other parts of your body if you already have one. Follow these simple guidelines:

  • Wash your hands regularly, especially if you’ve been in contact with someone with warts.
  • Don’t pick at your warts.
  • Cover warts with a bandage.
  • Keep your hands and feet dry.
  • Wear shower shoes (flip-flops) when in a locker room or communal bathing facility.

Warts generally aren’t dangerous, but they can be uncomfortable and sometimes painful. Many types respond to over-the-counter treatment, but it is best to make an appointment with a doctor if your wart changes in color, becomes painful, or if you suspect your wart may not be a wart.

Warts are contagious, but you can take precautions to keep from spreading or catching them, including washing your hands frequently and wearing shoes in communal locker rooms.