Warts are usually harmless, but may be unsightly. Warts on the feet are called verrucas and are sometimes painful. Warts and verrucas usually clear in time without treatment. If required, they can often be cleared more quickly with treatment. For example, by applying salicylic acid, or by freezing with liquid nitrogen or a cold spray, or by covering with tape.
What are warts and verrucas?
- Warts are small rough lumps on the skin. They are caused by a virus (human papillomavirus) which causes a reaction in the skin. Warts can occur anywhere on the body but occur most commonly on hands and feet. They range in size from 1 mm to over 1 cm. Sometimes only one or two warts develop. Sometimes several occur in the same area of skin. The shape and size of warts vary, and they are sometimes classed by how they look. For example: common warts, plane (flat) warts, filiform (finger-like) warts, mosaic warts, etc.
- Verrucas are warts that occur on the soles of the feet. They are the same as warts on any other part of the body. However, they may look flatter, as they tend to get trodden in.
Note: anal and genital warts are different. See separate leaflet called 'Warts - Anogenital' for more detail.
Who gets warts and verrucas and are they harmful?
Most people develop one or more warts at some time in their life, usually before the age of 20. About 1 in 10 people in the UK has warts at any one time. They are not usually harmful. Sometimes verrucas are painful if they press on a sensitive part of the foot. Some people find their warts unsightly. Warts at the end of fingers may interfere with fine tasks.
Are warts contagious?
Yes, but the risk of passing them on to others is low. You need close skin-to-skin contact. You are more at risk of being infected if your skin is damaged, or if it is wet and macerated, and in contact with roughened surfaces. For example, in swimming pools and communal washing areas.
You can also spread the wart virus to other areas of your body. For example, warts may spread round the nails, lips and surrounding skin if you bite warts on your fingers, or nearby nails, or if you suck fingers with warts on. If you have a poor immune system you may develop lots of warts which are difficult to clear. (For example, if you have AIDS, if you are on chemotherapy, etc.)
- To reduce the chance of passing on warts to others:
- Don't share towels.
- When swimming, cover any wart or verruca with a waterproof plaster.
- If you have a verruca, wear flip-flops in communal shower rooms and don't share shoes or socks.
- To reduce the chance of warts spreading to other areas of your body:
- Don't scratch warts.
- Don't bite nails or suck fingers that have warts.
- If you have a verruca, change your socks daily.
To treat or not to treat?
There is no need to treat warts if they are not causing you any problems. Without treatment, about 3 in 10 warts have gone within 10 weeks, and most warts will have gone within 1-2 years, and leave no scar. The chance that a wart will go is greatest in children and young people. Sometimes warts last longer. In particular, warts in older people are sometimes more persistent and may last for several years.
Treatment can often clear warts more quickly. However, treatments are time-consuming and some can be painful. Parents often want treatment for their children, but children are often not bothered by warts. In most cases, simply waiting for them to go is usually the best thing to do.
What are the treatment options?
The three most commonly used treatments are:
- Salicylic acid.
- Freezing treatment.
- Covering with duct tape.
Each of these is now discussed further.
There are various lotions, paints and special plasters that contain salicylic acid. You can buy these at pharmacies, or your doctor may prescribe one. Read the instructions in the packet on how to use the brand you buy or are prescribed, or ask your pharmacist for advice. Usually:
- You need to apply each day for up to three months. This acid burns off the top layer.
- Every few days rub off the dead tissue from the top of the wart, with emery paper (or similar). Gradually the wart is burnt off and rubbed away.
- It is best if you soak the wart in water for 5-10 minutes before applying acid.
- You should not apply acid to the face because of the risk of skin irritation which may cause scarring.
- If you have diabetes or poor circulation, you should use salicylic acid only on the advice of a doctor.
If you put the acid on correctly each day you have a good chance of clearing the warts within 3 months. Studies report that about 7-8 in 10 warts are cleared within 3 months with daily use of salicylic acid. Tips for success include:
- Try not to get the acid on the skin next to the wart, as it may become irritated. You can protect the nearby skin by putting some Vaseline® on the normal skin beforehand, or by putting on a plaster with a hole in it which just exposes the wart for treatment.
- If the surrounding skin does become sore, stop the treatment for a few days until it settles. Then re-start treatment. There is also a small risk that you may get a skin allergy to the treatment. If this occurs, the surrounding skin becomes red and itchy.
- It may take two weeks or more before you notice any improvement. It can take up to three months of daily applications for warts to go completely.
- Treatment may work better if you put a plaster on the wart after applying the acid.
- Acid lotions and paints are flammable. Keep them away from open fires and flames.
Freezing treatment (cryotherapy)
Freezing warts is a popular treatment. Many GPs and practice nurses are skilled at this. Liquid nitrogen is commonly used. The nitrogen is sprayed on or applied to the wart. Liquid nitrogen is very cold and the freezing and thawing destroys the wart tissue. To clear the wart fully it can need up to 4-6 treatment sessions, sometimes more. Each treatment session is a couple of weeks or so apart. Some studies show that the chance of clearing a wart with freezing treatment is about the same as acid treatment. However, one recent research study reported that freezing treatment was more likely to be successful at clearing warts compared with acid treatment. Also, freezing treatment tends to be quicker to get results.
Freezing treatment can be painful. Sometimes a small blister develops for a day or so on the nearby skin after treatment. Also, there is a slight risk of scarring the nearby skin or nail, or damaging underlying tissues such as tendons or nerves. It is not suitable for younger children or for people with poor circulation.
One review of treatments concluded that treatment with salicylic acid plus cryotherapy had a higher cure rate than either salicylic acid or cryotherapy alone.
One research study (cited at the end) found that covering a wart with strong adhesive tape seemed to give a good chance of clearing warts within a month or two. (Duct tape was used in the study.) In this study, about 7 in 10 warts had cleared within 2 months with using duct tape. The method described in the study was:
- The wart was covered with duct tape for 6 days. If the tape fell off during this time, a fresh piece of tape was put on.
- After 6 days, the tape was removed and the wart soaked in warm water for 5 minutes. After drying, it was then gently rubbed with an emery board or pumice stone to get rid of dead tissue from the top of the wart.
- The wart was then left uncovered overnight and duct tape put on again the next day.
- Treatment was continued for up to two months. (Note: most warts that cleared with duct tape did so within 28 days.)
However, two subsequent studies using tape (cited at the end) failed to demonstrate the good response of the first study. So, the evidence for tape treatment is mixed. But, it may be worth a try, as you are unlikely to do any harm and it may work. Some experts advise that you should not use duct tape on the face as in some people it can irritate the skin.
Other treatment options
A podiatrist or chiropodist can pare or rub down a verruca. This is often enough to ease any pain, even though part of the verruca may still remain.
If the above treatment options do not clear warts then other methods may be tried. There are various ways that can cut out or burn warts, but they are usually only done by specialists if other treatments have failed. Some treatments (such as laser treatment) are not available on the NHS to treat warts and verrucas.
What about swimming?
A child with warts or verrucas should go swimming as normal. Warts can be covered with waterproof plasters. A verruca can also be covered with a waterproof plaster but some people prefer to wear a special sock which you can buy from pharmacies. It is also a good idea to wear flip-flops when using communal showers, as this may reduce the chance of catching or passing on virus particles from verrucas.
Dr Tim Kenny
Dr Tim Kenny
Dr Beverley Kenny