Introduction

Warts are small lumps that often develop on the skin of the hands and feet.

Warts vary in appearance and may develop singly or in clusters. Some are more likely to affect particular areas of the body. For example, verrucas are warts that usually develop on the soles of the feet.

Warts are non-cancerous, but can resemble certain cancers.

Most people will have warts at some point in their life. They tend to affect children and teenagers more than adults.

Read more about the symptoms of warts.

What causes warts?

Warts are caused by an infection with the human papilloma virus (HPV).

The virus causes an excess amount of keratin, a hard protein, to develop in the top skin layer (epidermis). The extra keratin produces the rough, hard texture of a wart.

Read more about the causes of warts.

Are warts contagious?

Warts aren't considered very contagious, but they can be caught by close skin-to-skin contact. The infection can also be transmitted indirectly from contaminated objects or surfaces, such as the area surrounding a swimming pool.

You are more likely to get infected if your skin is wet or damaged. After you become infected, it can take weeks or even months for a wart or verruca to appear.

When to see your GP

Most types of warts are easy to identify because they have a distinctive appearance. You should always see your GP if you have a growth on your skin you are unable to identify or are worried about.

Your GP will be able to tell if it's a wart simply by looking at it. Where it is on your body and how it affects surrounding skin will also be taken into consideration.

You should visit your GP if you have a wart that:

  • bleeds
  • changes in appearance
  • spreads
  • causes you significant pain, distress or embarrassment

Treating warts

Most warts are harmless and clear up without treatment.

The length of time it takes a wart to disappear will vary from person to person. It may take up to 2 years for the viral infection to leave your system and for the wart to disappear.

You might decide to treat your wart if it is painful, or in an area that is causing discomfort or embarrassment.

Common methods of treatment include:

  • salicylic acid
  • cryotherapy (freezing the skin cells)
  • duct tape
  • chemical treatments

Treatment for warts is not always completely effective, and a wart will sometimes return following treatment.

Surgery is not usually recommended for warts.

Read more about how warts are treated.

Symptoms

Warts are not usually painful, but some types, such as verrucas, may hurt. They can occasionally itch or bleed.

There are several different types of warts, all varying in size and shape. The different types are described below.

Common warts (verruca vulgaris)

If you have a common wart, it will:

  • be round or oval-shaped
  • be firm and raised
  • have a rough, irregular surface similar to a cauliflower
  • often develop on the knuckles, fingers and knees
  • vary in size, from less than 1mm to more than 10mm (1cm) in diameter

You may develop one common wart or several.

Verrucas (plantar warts)

Verrucas usually develop on the soles of the feet. The affected area of skin will:

  • be white, often with a black dot (blood vessel) in the centre
  • be flat rather than raised
  • sometimes be painful if they are on a weight-bearing part of the foot 

Plane warts

It is possible to have between one and several hundred plane warts, which can develop in clusters. They are usually:

  • a yellowish colour
  • smooth, round and flat-topped
  • 2-4mm in diameter 
  • common in young children – mainly affecting the hands, face and legs

Plane warts can sometimes develop on the lower legs of women, as the human papilloma virus (HPV) can be spread through shaving. 

Filiform warts (verruca filiformis)

Filiform warts are long and slender in appearance, often developing on the neck or face.

Periungual warts

Periungual warts develop under and around the fingernails or toenails. They:

  • have a rough surface
  • can affect the shape of the nail
  • can be painful

Mosaic warts

Mosaic warts grow in clusters and form a "tile-like" pattern. They often develop on the palms of the hands and soles of the feet.

Causes

Warts are caused by certain strains of the human papilloma virus (HPV). The virus is present in the skin cells of a wart.

HPV is a family of viruses that affects the skin and moist membranes (mucosa) of the body.

There are more than 100 different strains of HPV. Different strains are responsible for different types of warts.

Spreading the virus

HPV is passed on through close skin-to-skin contact. It can also be transmitted indirectly by contact with contaminated objects, such as towels, shoes, areas surrounding swimming pools, or the floors of communal changing areas.

Warts are thought to be contagious for as long as they are present on your body. The virus is more likely to spread if the skin is wet, soft or has been in contact with a rough surface.

Warts can also be spread to other parts of your own body. You can spread the virus if you:

  • scratch, knock or bite a wart
  • bite your nails or suck your fingers (if they have warts on them)
  • shave your face or legs

This can cause the wart to break up and bleed, making it easier for the virus to spread. You are more vulnerable to verrucas if you have scratches or cuts on the soles of your feet.

Treatment

Warts usually clear up without treatment. However, it can take up to 2 years for the virus to leave your system and the warts to disappear.

The length of time it takes for a wart to disappear will vary from person to person. They tend to last longer in older children and adults.

In adults and people with a weakened immune system, warts are less likely to clear up on their own or respond well to treatment.

Leaving the wart to go away by itself is one option. However, you may want to consider treatment if your wart is painful, in an awkward position, or is causing you distress or embarrassment.

Your GP should always refer you to a specialist if you need treatment for a wart on your face.

Treatment options

There are a number of treatments available for warts. However, no single treatment is 100% effective, and the wart may return.

The aim of treatment is to remove the wart without it returning and without leaving any scarring.

Treatments include:

  • salicylic acid
  • cryotherapy
  • duct tape
  • chemical treatments

Surgery to treat warts is not usually recommended because warts often return and further treatment is required.

Some treatments may cause side effects such as mild pain, blistering and skin irritation around the wart.

These various treatments are described below.

Salicylic acid

Many wart and verruca treatments – including creams, gels, paints and medicated plasters – are available over the counter from pharmacies.

Salicylic acid is the active ingredient in most of these treatments. It has been shown that salicylic acid is as effective as cryotherapy for treating warts. 

There is limited evidence available to show which type of salicylic acid treatment (cream, gel, paint or plasters) is most effective.

Salicylic acid and other wart treatments also destroy healthy skin, so it is important to protect your skin before applying the treatment. You can use petroleum jelly or a corn plaster to cover the skin around the wart.

Before applying the treatment to your wart, use an emery board or pumice stone to file it down a little (avoid sharing the board or pumice stone with others). Repeat this about once a week while you are treating your warts.

Each time you treat your wart, soak it in water for about 5 minutes first to soften it, then follow the instructions that come with the medication.

You may need to apply the treatment every day for 12 weeks or longer. You should stop the treatment if your skin becomes sore, and seek advice from your GP or pharmacist.

Don't use treatments that contain salicylic acid to treat warts on your face. Ask your GP or pharmacist for advice about the best type of treatment.

Consult your GP before using over-the-counter treatments that contain salicylic acid if you have poor circulation – for example, if you have a condition like diabetes or peripheral arterial disease (PAD). This is because there is an increased risk of damage to your skin, nerves and tendons.

Cryotherapy

In cryotherapy, liquid nitrogen is applied to your wart for a few seconds to freeze and destroy the affected skin cells. After treatment, a sore blister will form, followed by a scab, which will fall off 7-10 days later.

A session of cryotherapy usually takes 5-15 minutes and can be painful. Large warts usually need to be frozen a few times before they clear up. You will probably need to wait a few weeks between each treatment.

There are 2 different cryotherapy methods. Liquid nitrogen may be sprayed directly onto the wart, or it may be applied using a stick with cotton wool on the tip. This second method is often preferred for treatment around the eyes or for small children.

Cryotherapy may be recommended if you have a wart on your face. This is because the risk of irritation is lower than when using salicylic acid or duct tape.

Cryotherapy is not usually recommended to treat young children because they may find the treatment too painful. It may also be difficult for them to stay in the same position while having the treatment.

If cryotherapy hasn't been successful within 3 months, further treatments aren't likely to be effective.

Possible side effects of cryotherapy include:

  • pain and blistering
  • your skin may become darker (hyperpigmentation) or lighter (hypopigmentation) – particularly if you have black skin
  • your nails may develop an abnormal change in shape or structure if cryotherapy is used to treat warts that develop around the nails (periungual warts)

Cryotherapy is sometimes carried out at GP surgeries or at hospital skincare clinics. However, it may not be available on the NHS in all areas of the country.

A very cold spray (dimethyl ether propane) is also available from pharmacies, which you can apply yourself. You should avoid using this spray on your face. Evidence suggests these sprays are not as effective as cryotherapy using liquid nitrogen.

Duct tape

Treatment with duct tape involves placing a piece of duct tape over your wart for about 6 days. If the tape falls off, simply replace it with a fresh piece. After 6 days, remove the tape and soak the wart in water.

After soaking the wart, use an emery board or pumice stone to get rid of any rough areas. Leave the wart uncovered overnight and apply a new piece of duct tape the following morning. This procedure should be repeated for a period of up to 2 months.

There is limited evidence to support the effectiveness of using duct tape to treat warts. However, side effects of this type of treatment are rare, although the skin can become irritated.

Chemical treatments

Warts can also be treated using chemical treatments available on prescription. The treatments contain chemicals such as:

  • formaldehyde 
  • glutaraldehyde 
  • silver nitrate

These chemicals are applied to the warts to kill affected skin cells. Potential side effects include the skin being stained brown (with glutaraldehyde) and burns to the surrounding skin (with silver nitrate). 

Treating warts during pregnancy

If you are pregnant and have warts, your GP may recommend using salicylic acid, cryotherapy or duct tape.

Salicylic acid can be used to treat warts during pregnancy, as long as it is used on a small area for a limited period of time.

Prevention

Most people will be infected by the human papilloma virus (HPV) at some point in their life and develop warts.

However, there are steps you can take to lower your chances of getting warts and prevent spreading them to others, if you have them.

To help prevent a wart or a verruca developing, you should:

  • not touch other people’s warts
  • not share towels, flannels or other personal items with someone who has a wart
  • not share shoes or socks with someone who has a verruca
  • avoid scratching or picking your wart or verruca because it will encourage the HPV to spread to other parts of your body
  • take care when shaving because the virus can be spread easily if you cut yourself
  • keep your feet dry, and change your socks every day to help prevent warts developing on your feet

If you have a wart or verruca, you should cover it up when taking part in communal activities. For example, you should:

  • wear pool slippers or flip flops in communal changing rooms and showers 
  • cover your wart or verruca with a waterproof plaster or a verruca sock when you go swimming, or while doing physical education at school
  • wear gloves when using shared gym equipment if you have a wart on your hand