Warts and verrucas

Introduction

Warts are small, skin-coloured, 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 are on the body and how thick the skin is. A wart on the sole of the foot is called a verruca.

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

The skin cells in warts release thousands of viruses, so close skin-to-skin contact can pass on the infection

Types of warts

There are several different types of warts, and some are more common than others. A UK study of 1,000 children with warts found that:

• 74% had common warts,
• 24% had verrucas,
• 3.5% had plane warts, and
• 2% had filiform warts.

See the Symptoms section for more information about each type of wart.

Who can get warts?

Most people have warts at some time during their life, usually before the age of 20. Warts are more common in children and teenagers than they are in adults. They are uncommon in babies.

Some people are more likely to get warts, such as those who have:

• atopic eczema, or
• weak immune systems (for example, following treatment for cancer, after an organ transplant, or due to an illness, such as AIDS).

Research has shown that warts on the hands can also be more common in people whose job involves handling meat, such as butchers and abattoir (slaughterhouse) workers. The reason for this is not known.

Warts are harmless but contagious

Warts can look unattractive, but they are usually harmless. They often clear up without treatment, but treatment can help to get rid of them more quickly. Warts are not normally painful, although verrucas can sometimes hurt.

Warts are very contagious. The skin cells in warts release thousands of viruses, so close skin-to-skin contact can pass on the infection. It is also possible to catch the infection indirectly from an object such as a towel. It can take weeks, or even months, for a wart or verruca to appear after you have caught the infection.

Genital warts

Genital warts occur on the genitals and around the rectum. They should not be treated at home. See Useful links for further information about genital warts, including how they are treated.

Symptoms of warts and verrucas

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

Warts are not normally painful, although warts under your fingernails, or on the soles of your feet (verrucas), can sometimes hurt.

You may have one or two warts, or you may have lots on the same area of your skin. Some types of warts affect particular parts of the body.

Common warts

Common warts (verruca vulgaris) are firm and raised, with a rough surface that can look a bit like a cauliflower. They can occur anywhere, but are most common on the hands (knuckles and fingers), elbows and knees.

You may have one, or several, common warts, but you will usually have less than 20.

Verrucas

Verrucas (plantar warts) are warts that occur on the soles of your feet. They can also occur on the heels and toes.

Verrucas do not stick up from the surface of the skin. Instead, the weight of your body pushing down on them makes them grow back into your skin, which can be painful.

Verrucas often have a black dot in the centre, surrounded by a hard, white area. The dot is the blood supply to the wart, and the white area is the skin of the wart that is closely packed together.

You may have one or several verrucas, but usually not more than 20.

Plane warts

Plane warts (verruca plana) are round, flat-topped and usually a yellowish colour. They are sometimes called flat warts, and usually occur in young children, mainly on the hands, face and legs. Plane warts are rare in adults.

You may have between one and 100 warts, which can sometimes be joined together.

Filiform warts

Filiform warts (verruca filiformis) are long, slender warts. They are common on the thin skin of the eyelids, armpits or neck.

Mosaic warts

Warts that grow in clusters are called mosaic warts. They occur mainly on your hands (palmar warts) and feet.

When to see your GP

You should see your GP if your wart or verruca:

• bleeds,
• changes in appearance, or
• spreads.

Foot specialists, known as podiatrists, can also give advice about verrucas.

Causes of warts and verrucas

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

How is the virus passed on?

The virus that causes warts is passed on through close skin-to-skin contact. It can also be passed on by indirect contact, for example, from objects such as towels and shoes. Warts are thought to be contagious for as long as they are present.

You can also spread warts to other parts of your own body. For example, you can spread the virus if you:

• scratch or bite a wart,
• bite your nails or suck your fingers, or
• 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 likely to catch the infection if your skin is:

• damaged,
• wet, or
• comes into contact with rough surfaces.

For example, public swimming pools are a common place to catch verrucas. People with scratches or cuts on the soles of their feet are particularly vulnerable.

Diagnosing warts and verrucas

Due to their distinctive appearance, warts and verrucas are usually easy to identify through a visual examination of the affected area. Your GP will be able to make a diagnosis.

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

Although a verruca is a type of wart, the weight of your body may have pushed it into your foot. It may appear as an area of very white skin on the sole of your foot, and may have a black dot in the centre.

Treating warts and verrucas

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.

Without treatment, warts usually clear up within two years, although some can take longer to go. It is also possible for warts to clear up without treatment within a few weeks, although this is less common.

There are several types of treatment that may help clear warts more quickly available. However, some treatments can be painful, and there is no guarantee that the warts will not come back again. Treatment can sometimes cause side effects including:

• irritated skin around the wart,
• pain, and
• blistering.

Treatment options for warts depend on their location and how many there are.

Salicylic acid

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

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

Soak the wart in water for about five minutes, and then follow the instructions on the packet to apply the medication. Some GPs recommend putting a plaster on the wart after you have applied the medication.

Rub the dead tissue off the wart once a week, using a pumice stone or emery board (do not share these with anyone else).

You may need to apply the treatment daily for up to 12 weeks, or longer. Stop the treatment if your skin becomes sore.

For warts on your face, avoid treatments containing salicylic acid and seek your GP’s advice about treatment.

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

Treatment with duct tape

There is limited evidence to support the effectiveness of treatment with duct tape. Side effects are uncommon. Using duct tape on the face is not recommended because it can irritate your skin.

Treatment involves covering the wart with a piece of duct tape (adhesive tape) for six days, and then removing it. You then soak the wart in warm water for five minutes and gently rub the dead tissue off using an emery board or pumice stone (do not share these with anyone else).

You should leave the wart uncovered overnight and apply a fresh piece of tape the following day. Treatment should be continued for up to two months.

Cryotherapy

In cryotherapy, very cold liquid such as nitrogen is sprayed on to the wart to freeze and destroy the cells. A sore blister develops, followed by a scab, which falls off seven to 10 days later.

Treatment usually takes between five and 15 minutes and can be painful, so you might need a local anaesthetic beforehand.

Cryotherapy treatment is usually carried out at hospital skin clinics, or at your GP surgery. Large warts sometimes need to be frozen several times, a week or so apart, before they clear.

If you have a wart on your face, your GP may recommend cryotherapy treatment because the risk of irritation is lower than using salicylic acid or duct tape.

A very cold spray (dimethyl-ether/propane) is also available from pharmacies, which you can apply yourself. Do not use this spray on your face.

Treatment for warts during pregnancy

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

Salicylic acid may be used to treat warts during pregnancy, as long as it is used on a small area for a limited period of time. However, you may prefer to wait until after the birth before considering treatment.

Surgery

Warts are not normally treated with surgery because they often come back afterwards. Surgery also usually causes scarring.

If surgery to remove warts is recommended, it will usually be carried out under general or local anaesthetic. 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. The aim of surgical treatment is to remove all traces of the warts.

Other surgical options include:

• laser treatment, where the wart is destroyed using a very precise laser beam,
• electrocautery, where the wart is burnt off using an electric current, and
• photodynamic therapy, where the wart cells absorb a chemical that destroys them when activated by light (usually from a laser).

Some of these treatments may not be available on the NHS.

Chemical treatments

Treatments containing chemicals such as formaldehyde, glutaraldehyde and podophyllin can be used to remove warts. These chemicals are poisonous to skin cells, and are dabbed onto the warts in order to kill the skin cells there. Chemical treatments are available on prescription.

Complications of warts and verrucas

Lack of confidence

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.

Complications relating to treatment

Common complications after treatment include:

• pain, and
• irritated skin around the wart.

Rarely, treatment for warts can cause scarring and infection.

It can be very difficult to treat warts in people with weak immune systems (for example, people with an illness such as AIDS or people who have had an organ transplant or treatment for cancer). In some cases, it may not be possible to clear the warts, even with treatment.

Malignant change

Warts are usually harmless in people whose immune systems are working properly, and it is rare for any malignant change in a wart to develop.

However, in people whose immune systems are weak (see above), there is a higher risk of a wart becoming malignant.

Preventing warts and verrucas

Follow the steps below in order to reduce your chances of getting a wart or verruca.

• 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.

If you have a wart or a verruca, do not scratch or pick it because this can spread the infection to other parts of your body.

Communal activities

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

• Wear flip-flops in shared areas such as showers and swimming pool changing rooms.
• Cover your wart or verruca with a waterproof plaster when you go swimming, or when doing physical education (PE) at school. You can also buy special socks to cover verrucas. These are available at pharmacies.
• If you have a wart on your hand, wear gloves when you are using shared equipment, such as gym equipment.

References

• BAD (2005) Plantar warts (verrucas). British Association of Dermatologists. Available from: www.bad.org.uk
• Bigby M, Gibbs S (2005) Warts. BMJ Clinical Evidence. www.clinicalevidence.com
• Gibbs S, Harvey I (2006) Topical treatments for cutaneous warts (Cochrane Review). The Cochrane Library. Issue 3. Available from www.thecochranelibrary.com
• Health Protection Agency (2003) Guidelines on the management of communicable diseases in schools and nurseries: warts and verrucas. London: Health Protection Agency. Available from www.hpa.org.uk
• Lowy DR, Androphy EA (1999) Warts. In: Fradberg IM, et al (Eds.) Fitzpatrick's Dermatology in General Medicine. 5th edn. New York: McGraw-Hill.
• Sterling JC, et al (2001) Guidelines for the management of cutaneous warts. British Journal of Dermatology 144(1), 4-11
• Sterling JC, Kurtz JB (1998) Viral infections. In: Champion RH et al. (Eds.) Textbook of Dermatology. 6th edn. Oxford: Blackwell Science. 995-1096