Condition Overview

Is this topic for you?

What are warts, and what causes them?

A wart is a skin growth caused by some types of the virus called the human papillomavirus (HPV). HPV infects the top layer of skin, usually entering the body in an area of broken skin. The virus causes the top layer of skin to grow rapidly, forming a wart. Most warts go away on their own within months or years.

Warts can grow anywhere on the body, and there are different kinds. For example, common warts grow most often on the hands, but they can grow anywhere. Plantar warts grow on the soles of the feet.

How are warts spread?

Warts are easily spread by direct contact with a human papillomavirus. You can infect yourself again by touching the wart and then touching another part of your body. You can infect another person by sharing towels, razors, or other personal items. After you've had contact with HPV, it can take many months of slow growth beneath the skin before you notice a wart.

It is unlikely that you will get a wart every time you come in contact with HPV. Some people are more likely to get warts than others.

What are the symptoms?

Warts come in a wide range of shapes and sizes. A wart may be a bump with a rough surface, or it may be flat and smooth. Tiny blood vessels grow into the core of the wart to supply it with blood. In both common and plantar warts, these blood vessels may look like dark dots in the wart's centre.

Warts are usually painless. But a wart that grows in a spot where you put pressure, such as on a finger or on the bottom of the foot, can be painful.

How are warts diagnosed?

A doctor usually can tell if a skin growth is a wart just by looking at it. Your doctor may take a sample of the wart and look at it under a microscope (a skin biopsy). This may be done if it isn't clear that the growth is a wart. It may also be done if a skin growth is darker than the skin surrounding it, is an irregular patch on the skin, bleeds, or is large and fast-growing.

How are they treated?

Most warts don't need treatment. But if you have warts that are painful or spreading, or if you are bothered by the way they look, your treatment choices include:

• Using a home treatment such as salicylic acid or duct tape. You can get these without a prescription.
• Putting a stronger medicine on the wart, or getting a shot of medicine in it.
• Freezing the wart (cryotherapy).
• Removing the wart with surgery (electrosurgery, curettage, laser surgery).

Wart treatment doesn't always work. Even after a wart shrinks or goes away, warts may come back or spread to other parts of the body. This is because most treatments destroy the wart but don't kill the virus that causes the wart.

Cause

A wart develops when a human papillomavirus (HPV) infects the outer layer of skin and causes the skin cells to grow rapidly. The virus can then spread from an existing wart to other areas of the body, causing more warts. Various types of this virus thrive in warm, damp environments such as showers, locker room floors, and swimming pool areas.

You are most likely to develop a wart where you have broken skin, such as a cut, a hangnail, a closely bitten nail, or a scrape. Plantar warts are common in swimmers whose feet are not only damp and softened but are also scratched and broken by rough pool surfaces. Common warts are often seen among those who handle meat, chicken, and fish.

How are warts spread?

Warts are easily spread by direct contact with a human papillomavirus. You can reinfect yourself by touching the wart and then touching another part of your body. You can infect others by sharing towels, razors, or other personal items. After exposure to a human papillomavirus, it can take many months of slow growth beneath the skin before you notice a wart.

It is unlikely that you will develop a wart every time you are exposed to a human papillomavirus. Some people are more likely to develop warts than others.

Can common warts on hands or fingers be spread to the genitals and cause genital warts?

It depends. There are many types of HPV, and the types that cause common warts are usually different from those that cause plantar warts and genital warts. If the wart on a person's hand is caused by a type of HPV that can also cause genital warts, then there is a chance that skin contact could cause genital warts.

But common warts don't cause the type of genital warts that lead to high-risk cancers.

Symptoms

Warts occur in a variety of shapes and sizes. A wart may appear as a bump with a rough surface, or it may be flat and smooth. Tiny blood vessels (capillaries) grow into the core of the wart to supply it with blood. In both common and plantar warts, these capillaries may appear as dark dots (seeds) in the wart's centre.

• Common warts usually appear singly or in groups on the hands, although they may grow on any part of the body. They usually are rough, grey-brown, dome-shaped growths.
• Plantar warts can develop on any part of the foot. As the callus and wart get larger, walking can become painful, much like walking with a pebble in your shoe. When pressure from standing or walking pushes a plantar wart beneath the skin's surface, a layer of thick, tough skin similar to a callus develops over it. Sometimes dark specks are visible beneath the surface of the wart.
• Flat warts are usually found on the face, arms, or legs. They are small (usually smaller than the eraser on the end of a pencil). There are usually several in one area. They have flat tops and can be pink, light brown, or light yellow. Flat warts are often spread by shaving.
• Filiform warts, a kind of flat wart, can grow around the mouth, nose, and beard area. The surface of this type of wart has many flesh-coloured, finger-shaped growths.
• Periungual warts are found under and around the toenails and fingernails. They appear as rough, irregular bumps.

Warts cover the lines and creases in the skin—this is one way to tell a wart from other skin conditions, such as skin tags or moles.

What Happens

Human papillomaviruses can live on healthy skin without causing infection. But when a human papillomavirus enters the body through small breaks in the skin, it can infect the skin cells beneath the surface, causing a wart to grow.

• A wart can take many months to grow before it becomes visible.
• Warts, particularly newer ones, are easily spread. They can spread to other parts of the body or to other people.
• Plantar warts can be pushed beneath the skin's surface by pressure from standing and walking. A thickening of the skin slowly forms over most of the wart and looks and feels like a callus.
• Periungual warts can affect nail growth.
• It may be hard to get rid of warts after they develop. But they generally go away on their own within months or years.
• Just before warts disappear on their own, they may turn black.

What Increases Your Risk

Risk factors for warts include:

• Having an impaired immune system.
• Your age. Warts occur most often in children and young adults. As you get older, you may find that you get fewer warts or that your warts go away.
• Walking barefoot on moist surfaces, as in public showers and locker rooms and around swimming pool areas.
• Sharing towels, razors, and other personal items with a person who has warts.
• Biting your nails or cuticles.
• Wearing closed or tight shoes that cause sweaty feet.

When To Call

See your doctor if:

• You aren't sure if a skin growth is a wart. If you are older than age 60 and have never had warts, consider seeing your family doctor or other health professional to check for skin cancer.
• Non-prescription home treatment isn't successful after 2 to 3 months.
• Warts are growing or spreading rapidly despite treatment.
• Signs of bacterial infection develop, including:
  
  • Increased pain, swelling, redness, tenderness, or heat.
  • Red streaks extending from the area.
  • Discharge of pus.
  • Fever.
• A plantar wart becomes too painful to walk on.
• You have diabetes or peripheral arterial disease and you need treatment for a wart on a leg or foot.
• You have warts on your genitals or around the anus.

Watchful waiting

Watchful waiting is a period of time during which you and your doctor observe your symptoms or condition without using medical treatment. It is often appropriate treatment for warts, because they generally go away on their own within months or years. But you may want to consider treating a wart to prevent it from spreading to other parts of your body or to other people. You can try a non-prescription wart treatment for 2 to 3 months before deciding to see a doctor.

Who to see

Your family doctor or general practitioner can diagnose and treat warts. You may be referred to a specialist, such as a dermatologist or a podiatrist.

Examinations and Tests

Warts are usually diagnosed based only on their appearance.

In rare cases, more testing is done. If the diagnosis of a skin condition is unclear or if you are at high risk for having skin cancer, your doctor may take a sample of the growth and examine it (a skin biopsy). A biopsy is usually done if a skin growth is darker than the skin surrounding it, appears as an irregular patch on the skin, bleeds, or is large and growing rapidly.

Proper diagnosis of plantar warts is important. Some wart treatments can cause scarring.

Treatment Overview

Not all warts need to be treated. They generally go away on their own within months or years. This may be because, with time, your immune system is able to destroy the human papillomavirus that causes warts.

You may decide to treat a wart if it is:

• Painful.
• Embarrassing.
• Easily irritated.
• Growing or spreading to other parts of your body or to other people.

The goal of wart treatment is to destroy or remove the wart without creating scar tissue, which can be more painful than the wart itself. How a wart is treated depends on the type of wart, its location, and its symptoms. Also important is your willingness to follow a course of treatment that can last for weeks or months.

Wart treatment isn't always successful. Even after a wart shrinks or disappears, warts may return or spread to other parts of the body. This is because most treatments only destroy the wart and don't kill the virus that causes the wart.

• Warts: Should I Treat Warts?

Treating the warts yourself

Many people don't treat warts unless they are unsightly or painful. You can treat warts yourself with:

• Salicylic acid.
• Duct tape (tape occlusion).

If your child has a wart, treatment probably isn't needed. That's because warts often go away on their own. But if the wart is on your child's face or genitals or is painful or spreading, your child should see a doctor for treatment. Otherwise, it is usually safe to treat a wart at home with duct tape or salicylic acid. If the wart doesn't start to improve within 2 weeks, see your doctor.

For more information, see Home Treatment.

If you have diabetes or peripheral arterial disease, talk to your doctor before you try home treatment for warts.

Treatment by your doctor

Your doctor can treat warts with:

• Cryotherapy. For more information, see Other Treatment.
• Medicines, such as retinoid cream, cantharidin, or imiquimod.
• Surgery, such as electrosurgery and curettage and laser surgery.
• Chemical peels with glycolic acid, tretinoin, or a stronger formula of salicylic acid.

What to think about

It's important to distinguish a plantar wart from a callus before choosing a treatment. Wart treatment applied to a callus may be painful or create scar tissue.

Plantar warts are often hard to treat because they lie beneath the skin. A doctor may need to pare the skin over a wart to help the medicine penetrate the wart.

Before treating your warts, think about:

• The potential for scarring. Scarring is the most important thing to think about when choosing a wart treatment. Scarring from treatment may be permanent and can be as painful as the wart itself. The bottom of the foot is especially sensitive, a consideration in the case of plantar warts. And scarring changes the way your skin looks. Treatments that are less likely to leave a scar include salicylic acid, cryotherapy, and laser surgery.
• The cost. Home treatment is often as effective as treatment by a doctor. But home treatment may take longer. Less expensive home treatments include tape occlusion (duct tape) and non-prescription salicylic acid.
• Your ability to tolerate pain. Quicker but more painful methods include some topical medicines (such as cantharidin) and cryotherapy.
• Your risk of infection. Treatment can sometimes cause infection. If you have an impaired immune system or a condition such as diabetes or peripheral arterial disease, discuss your increased risk of infection with your doctor. You may need to take special precautions.
• Your history of recurrent warts. If you have a history of warts that come back, you may want to talk with your doctor about more aggressive treatment methods.
• The location and number of warts. Large areas covered by warts may be better treated with salicylic acid than with more painful, potentially scarring methods.
• Your age. Painful treatments, such as cryotherapy, may not be appropriate for young children. If you are older than age 60 and have never had warts, you may want to see a doctor to check any skin growths for skin cancer.
• The time needed for treatment. Topical (putting medicine on the wart) treatment is often slower than surgical treatment. Some treatment methods, such as immunotherapy applied by a health professional, require repeated office visits. In such cases, the expense and inconvenience may outweigh the benefits of treatment.

Prevention

The main way to prevent warts is to avoid contact with the human papillomavirus (HPV) that causes warts. If you are exposed to this virus, you may or may not get warts, depending on how susceptible you are to the virus.

Tips on avoiding the human papillomavirus

• Avoid touching warts on yourself or others.
• Don't share razors, towels, socks, or shoes with another person. Someone with no visible warts can still be carrying the virus.
• Avoid walking barefoot on warm, moist surfaces where the wart virus may be alive. Wear shower shoes when using public showers, locker rooms, or pool areas.
• Keep your feet dry. If your feet sweat heavily, wear socks that absorb moisture or wick it away from the skin.
• Avoid irritating the soles of your feet. Warts grow more easily if your skin has been injured or broken in some way.

Tips on preventing warts from spreading

• Keep warts covered with a bandage or athletic tape.
• Don't bite your nails or cuticles, as this may spread warts from one finger to another.

Self-Care

Home treatment is often the first treatment used for warts. When done properly, home treatment is usually less painful than surgical treatment.

Home treatment includes:

• Salicylic acid, which is currently considered the most desirable wart treatment, based on its effectiveness and safety. The treatment takes 2 to 3 months. Salicylic acid formulas include Compound W and Occlusal. Ask your doctor about how to use salicylic acid.
• Tape occlusion (duct tape), in which you use duct tape to cover the wart for a period of time. This treatment takes 1 to 2 months.
• Over-the-counter cryotherapy. There are home cryotherapy kits that you can buy without a prescription, such as Dr. Scholl's Freeze Away. These treatments may be safe for warts on the hands or feet but not for genital warts. Follow all instructions carefully.

If you are uncertain that a skin growth is a wart, or if you have diabetes, peripheral arterial disease, or other major illnesses that may affect your treatment, it is best to see a health professional.

Reducing plantar wart pain

You can reduce plantar wart pain by:

• Wearing comfortable shoes and socks. Avoid high heels or shoes that increase pressure on your foot.
• Padding the wart with doughnut-shaped felt or a moleskin patch that can be purchased at pharmacies. Place the pad around the plantar wart so that it relieves pressure on the wart. Also, consider placing pads or cushions in your shoes to make walking more comfortable.
• Using non-prescription medicines, such as aspirin, ibuprofen (such as Advil), or acetaminophen (such as Tylenol) to help relieve pain. Do not give aspirin to anyone younger than 18, because of the risk of Reye syndrome, a serious but rare illness. Be safe with medicines. Read and follow all instructions on the label.

What to think about

Salicylic acid treatments are often effective. They aren't very painful, aren't very expensive, and usually don't cause scarring. Salicylic acid is a good treatment for children because it isn't very painful. For treatment to be successful, salicylic acid must be applied on a regular basis, usually for a number of months.

Folk remedies, such as rubbing a wart with a bean, may have an effect on a wart. But such treatment may simply coincide with the natural disappearance of a wart.

Never cut or burn off a wart yourself.

Medicines

If you decide to treat your warts, both non-prescription and prescription medicines are available.

• Warts: Should I Treat Warts?

Non-prescription medicines

Non-prescription medicines include:

• Salicylic acid, which softens the skin layers that form a wart so that they can be rubbed off. Salicylic acid formulas include Compound W and Occlusal.

Prescription medicines

Medicines that your doctor may use or prescribe for you include:

• Retinoid cream (Retin-A, Stieva-A). It disrupts the wart's skin cell growth.
• Cantharidin (Canthacur-PS, Cantharone Plus). This medicine causes the skin under the wart to blister, lifting the wart off the skin. This medicine is applied to the wart at your doctor's office.
• Immunotherapy medicines, which help your body's immune system fight viruses, including the human papillomavirus (HPV) that causes warts. These medicines may include imiquimod, contact sensitizers, and interferon.
• Bleomycin injection, which destroys the skin containing the wart. But bleomycin isn't often used, because it is painful during and after the injection.

What to think about

Other medicines used for warts include 5-fluorouracil, which is more often used on genital warts, and cimetidine. Cimetidine can be taken by mouth (orally) or as an injection.

As with any medicine, talk to your doctor before using a wart medicine if you are or may be pregnant. Some wart medicines may cause birth defects.

Surgery

Surgery is an option if home treatment and treatment at your doctor's office have failed. Surgery for warts is usually quick and effective. No single surgical method is more effective than another in removing warts. Generally, doctors start with the surgical method that is least likely to cause scarring.

Surgery choices

The most common types of surgical treatment for wart removal include:

• Electrosurgery and curettage. Electrosurgery is burning the wart with an electrical current. Curettage is cutting off the wart with a sharp knife or a small, spoon-shaped tool. The two procedures are often used together.
• Laser surgery. Laser surgery burns off the wart with an intense beam of light.

What to think about

A wart may return after surgery, because surgery removes the wart but doesn't destroy the virus that causes the wart.

The type of surgery used to remove warts depends on the warts' type, location, and size. Curettage, electrosurgery, and laser surgery are more likely than cryotherapy to leave scars, so they are usually reserved for hard-to-remove or recurring warts. If you have a large area of warts, curettage may not be an effective treatment.

Some surgical treatments may be too painful for some children.

Other Treatment

Cryotherapy, which uses a very cold liquid to freeze a wart, is the most commonly used procedure that doesn't involve medicine to treat warts. This procedure poses little risk of scarring but can be painful.

• Warts: Should I Treat Warts?