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Warts And Verrucas

Warts are small, rough lumps on the skin that are benign (non-cancerous). They often appear on the hands and feet.

Warts can look different depending on where they appear on the body and how thick the skin is. A wart on the sole of the foot is called a verruca. The clinical name for a verruca is a plantar wart.

Warts are caused by infection with a virus known as the human papilloma virus (HPV). HPV causes keratin, a hard protein in the top layer of the skin (the epidermis) to grow too much. This produces the rough, hard texture of a wart.

Types of warts

There are several different types of warts. The more common types include:

• common warts
• plantar warts (verrucas)
• plane warts
• filiform warts
• periungual warts 
• mosaic warts

The appearance of each type of wart will depend on several factors:

• where it is located on your body
• the strain (type) of HPV that is responsible for the wart
• factors such as whether you have a weakened immune system
• whether you have rubbed or knocked the wart

See Warts and verrucas - symptoms for more information about each type of wart.

Who gets warts

Most people will have warts at some time during their life. However, they are more common in school children and teenagers than in adults. Research has indicated that 4-5% of children and adolescents in the UK have warts.

Warts are uncommon in babies and occur in equal numbers between males and females.

People who have an increased risk of developing warts include those with weak immune systems, for example, following treatment for cancer or due to an illness such as HIV and AIDS, and those who have had an organ transplant. Around 50% of people who have had a kidney transplant develop warts within five years.

A type of wart that is known as a ‘butcher's wart’ can sometimes develop on the hands of people who are regularly in contact with raw meat, fish or poultry for long periods of time. However, this type of wart is rare.

Genital warts

Like other types of warts, genital warts are caused by HPV. Genital warts are most commonly transmitted during sexual intercourse and other types of sexual activity, including oral sex.

Genital warts should not be treated at home using over-the-counter medicines. If you think you have genital warts, visit your GP or local sexual health clinic.

See the Health A-Z topic about Genital warts for more information and advice.

Outlook

Most warts disappear on their own without treatment, although treatment can help to get rid of them more quickly. Treatment may be recommended in cases where:

• the wart is causing you pain or distress
• there are associated risk factors, such as having a weakened immune system

Several treatment options are available to help treat warts and verrucas successfully. See Warts and verrucas - treatment for more information.

Symptoms

There are several different types of warts which all vary in size and shape. For example, the size of a wart can range from 1mm to over 1cm in diameter.

Warts are not usually painful, although those that develop under your fingernails (periungual warts) or on the soles of your feet (verrucas) can sometimes hurt. Warts can also occasionally itch or bleed.

You may have one or two warts or you may have a cluster of several warts on the same area of your skin. Some types of warts are more likely to affect particular areas of your body. These are described below.

Common warts (verruca vulgaris)

Characteristics of common warts include:

• round or oval in shape
• they are firm and raised
• they have a rough, irregular surface (cauliflower-like)
• they are most common on the knuckles, fingers and knees
• they range in size from smaller than 1mm to larger than 10mm
• you may have one or several common warts

Verrucas (plantar warts)

Characteristics of verrucas include:

• the skin area of the wart is white
• they often have a black dot in the centre (blood vessel)
• they are not raised from the surface of your skin
• they appear on the soles of your feet
• they can be painful because the weight of your body can force them to grow back into the skin

Plane warts

Characteristics of plane warts include:

• they are a yellowish colour
• they are smooth, round and flat-topped
• they are usually between 2 and 4mm in diameter 
• they usually occur in young children, mainly on the hands, face and legs
• they can appear on the lower legs of females (due to the spread of HPV through leg shaving)
• it is possible to have between one and several hundred plane warts, which can develop in clusters

Filiform warts (verruca filiformis)

Characteristics of filiform warts include:

• they are long and slender
• they more commonly develop on the neck, face and nostrils

Periungual warts

Characteristics of periungual warts include:

• they have a rough surface
• they are found under and around the fingernails and toenails
• they can affect the shape of the nail
• they can be painful

Mosaic warts

Characteristics of mosaic warts include:

• they grow in clusters
• the pattern that mosaic warts produce is ‘tile-like’
• they are most common on the palms of the hands (palmar warts) and on the feet

Causes

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

Over 100 different types (strains) of HPV have been identified. Different strains of HPV are responsible for causing different types of warts.

Spreading the virus

HPV is passed on through close skin-to-skin contact. It can also be passed on by indirect contact, for example, from contaminated objects, such as towels and shoes. Warts are thought to be contagious for as long as they are present on your body.

HPV 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. For example, 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. People with scratches or cuts on the soles of their feet are particularly vulnerable.

Warts can also be spread through contact with contaminated surfaces. Examples of possible contaminated surfaces include:

• the areas surrounding swimming pools
• communal washing areas

Diagnosis

Your GP will be able to diagnose the type of wart that you have based on:

• the appearance of your wart
• where it is positioned on your body
• the effect it has had on the surrounding skin

Due to their distinctive appearance, warts and verrucas are usually easy to identify through a visual examination of the affected area. Your GP will consider the following when they examine your wart:

• the number of warts you have
• where they are located on your body
• the size of the wart
• the shape of the wart
• the colour of the wart
• the texture of the wart’s surface

Your GP may gently cut away the surface of the wart to reveal a small black dot in the centre. If this is present, it will confirm that you have a verruca (plantar wart).

If you have a partner, your GP may ask you whether they also have warts, or whether any other members of your family have them.

Ruling out other conditions

By carrying out a thorough examination of your wart, your GP will also be able to consider any other possible causes and rule out any underlying conditions. Some of these are outlined below.

• Corns and calluses: areas of thick, dry skin that are often yellow in appearance and caused by excessive pressure or friction.
• Skin tag: a skin-coloured, benign (non-cancerous) growth of skin that usually develops on the neck, armpit and torso (upper body). Skin tags are usually painless.
• Molluscum contagiosum: a contagious skin infection that is caused by the molluscum contagiosum virus. It produces small, firm, raised spots on the skin.
• Moles: small, dark marks on your skin that can be flat or raised, smooth or rough. They may sometimes look similar to a cluster of filiform warts.
• Seborrhoeic keratosis: common, benign skin lesions that are usually brown or black in colour.
• Solar keratosis: scaly, rough spots that appear on skin that has been damaged by the sun.
• Squamous cell carcinoma: a common type of skin cancer that appears as crusted lumps that are tender and slow-growing. It is very rare for existing warts to develop into a type of cancer, but the possibility will need to be ruled out.

Referral to a specialist

If your GP is concerned about your wart after carrying out an examination, they may refer you to a skin specialist (dermatologist) who will be able to assess your wart and confirm a diagnosis. However, in most cases, referral to a dermatologist is not necessary.

Treatment

Most warts clear up without treatment. However, the time it takes for a wart to disappear will vary from person to person. Warts may last longer in older children and adults.

Research has shown that without treatment, 65-80% of cases of warts will clear up within two years. However, warts in adults and in people with a weakened immune system are less likely to clear up on their own and are less likely to respond well to treatment.

Leaving the wart to get better by itself is an option that may be recommended. However, treatment will be considered if:

• the wart is causing you pain
• the wart is interfering with your everyday life
• the wart or its position is causing you embarrassment
• you have one or more of the potential risk factors for developing cancer (see Warts and verrucas - diagnosis)

Treating warts

Several treatment options are available for treating warts and verrucas. Some treatments for warts can cause side effects such as:

• pain
• blistering
• skin irritation around the wart

The aim of all types of treatment is to:

• remove the wart without it returning
• treat the wart without any scarring developing as a result
• encourage long-lasting immunity to HPV, which causes warts

No single treatment for warts is 100% effective, and there is no guarantee that the warts will not return. Treatment for warts includes:

• salicylic acid
• cryotherapy
• duct tape
• surgery
• chemical treatments

These are described in more detail below.

Salicylic acid

Many treatments, such as creams, gels, paints and medicated plasters, are available over the counter from pharmacies. The active ingredient in most of these treatments is salicylic acid. In two-thirds of cases, research has shown that hand warts clear up within 12 weeks of treatment with salicylic acid.

There is limited evidence available to show which type of salicylic acid treatment (ointment, cream or gel) is most effective. However, it has been shown that salicylic acid is effective at treating warts.

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 to rub any excess outer skin on the affected area (avoid sharing these with others). Then soak the wart in water for around five minutes to soften the skin.

After soaking your wart, follow the treatment instructions that came with the medication. You may need to apply the treatment daily for 12 weeks or longer. However, stop the treatment if your skin becomes sore and seek advice from your GP or pharmacist.

If you have warts on your face, avoid using treatments that contain salicylic acid and seek your GP’s advice about the best type of treatment.

If you have poor circulation, for example, if you have a condition such as diabetes or peripheral vascular disease, consult your GP before using over-the-counter treatments that contain salicylic acid. This is because there is an increased risk of damage to your skin, nerves and tendons.

Cryotherapy

In cryotherapy, liquid nitrogen is sprayed onto the wart to freeze and destroy the cells. A sore blister develops, followed by a scab, which falls off seven to ten days later.

Cryotherapy treatment usually takes 5-15 minutes and can be painful. Treatment is usually carried out at hospital skin clinics or at your GP surgery. Large warts sometimes need to be frozen a number of times, a week or so apart, before they clear up.

The exact method of cryotherapy that is used may differ between healthcare professionals. Liquid nitrogen may be sprayed directly onto the wart or it may be applied using a stick with cotton wool on the tip. This method may be 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 for this method is lower than using salicylic acid or duct tape.

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

Possible side effects of cryotherapy include:

• pain
• 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 periungual warts

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. There is a lack of evidence to support the effectiveness of dimethyl-ether/propane spray compared with cryotherapy with liquid nitrogen.

Duct tape

Treatment with duct tape involves placing a piece of duct tape over your wart for about six days. If the tape falls off you simply replace it with a fresh piece. After six days the tape is removed and the wart is soaked in water.

After soaking the area in water, use an emery board to rub away any rough areas. The wart should be left uncovered overnight and a new piece of duct tape applied the following morning. This procedure is then repeated for a period of up to two months.

There is limited evidence to support the effectiveness of treatment with duct tape. Limited research has shown that side effects are uncommon. However, in some cases, skin irritation may occur and the tape could easily fall off.

If you are considering using duct tape, you may want to discuss it with your GP so that you are fully aware of the treatment’s potential benefits and weaknesses.

Surgery

In most cases, surgery is not recommended for treating warts because they often come back afterwards. It is estimated that the wart returns and further treatment is needed in around a third of cases where surgery is used to remove warts.

The aim of surgical treatment is to remove all traces of the warts. The techniques that are sometimes used to remove warts surgically are:

• curettage, where tissue is removed by scraping
• cautery, where tissue is destroyed by burning using an instrument or an electric current

Surgery to remove warts will usually be carried out under local anaesthetic. The anaesthetic will numb the affected area so that you will not feel any pain during the procedure.

Warts can be cut out of the skin (which can be useful if you have a few, large warts) or the skin of the wart can be scraped off using a spoon-like instrument called a curette. However, this type of surgery is usually avoided for warts and verrucas on the soles of the feet because of the risk of scarring.

Chemical treatments

Warts can also be treated using chemical treatments that contain chemicals such as:

• formaldehyde
• glutaraldehyde
• podophyllin

These chemicals are poisonous to skin cells and are dabbed on to the warts to kill the skin cells. Chemical treatments are available on prescription.

Potential side effects of chemical treatments include:

• staining the skin brown (with glutaraldehyde)
• intense swelling (with podophyllin)
• infection following treatment (with podophyllin)

Complications

After treatment

Following treatment for warts, common side effects include:

• pain
• blistering
• irritation of the skin around the wart

Treatment for warts rarely causes scarring and infection.

It is sometimes very difficult to treat warts effectively in people with weak immune systems, such as those with an illness like HIV and AIDS or those receiving treatment for cancer. In some cases, clearing up the warts may not be possible, even with treatment.

Psychological effects

If you feel that your warts look unattractive, it may affect your confidence and self-esteem, particularly if they cover a large area of your body. Warts can sometimes affect a person psychologically and have an adverse impact on day-to-day life.

Malignancy

Warts are usually harmless in people whose immune systems are working properly, and it is rare for any malignant (cancerous) change to develop in a wart. However, people with a weakened immune system have a higher risk of a wart becoming malignant.

Prevention

The advice listed below can help to prevent a wart or a verruca developing.

• Do not touch other people’s warts.
• Do not share towels, flannels or other personal items with someone who has a wart.
• Do not share shoes or socks with someone who has a verruca.
• Avoid scratching or picking your wart or verruca as this will encourage 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.

Communal activities

Cover your wart or verruca when you are taking part in communal activities. For example:

• wear flip-flops or pool slippers in shared areas, such as showers and swimming pool changing rooms
• cover your wart or verruca with a waterproof plaster or a special verruca sock (available at pharmacies) when you go swimming or when you are doing physical education at school
• wear gloves when using shared equipment, such as gym equipment (if you have a wart on your hand)