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A. What are warts?

Warts are a viral infection of the skin which may affect the face, hands or feet. When they occur on the feet they are often referred to as verruccae. They are more common in children with chronic kidney disease and in those who have had a kidney transplant because of a reduced ability of the immune system to fight off the warts. Although they are unsightly they are generally harmless.

B. Are warts contagious?

Warts are contagious but need close skin-to-skin contact to be transmitted. They can also be passed from one part of the skin to another, eg from the hands to the face. It is therefore important to avoid scratching warts and sucking your fingers or biting your nails if you have warts on your hands. You should wear slip-ons if bathing in a public place.

C. What do I do if I think my child may have warts?

If you think your child may have warts then discuss this with your pharmacist, GP or with your doctor at your next clinic visit. A recent survey in our unit shows that in the majority of cases they can be treated with simple methods available at your local pharmacy or via your GP.

D. What do I do if I think the treatment is not effective?

It may take some months before the treatment removes all the warts. If topical treatment from the chemist is not effective, the warts may respond to further treatment available from your GP. If they persist despite this or your child is very unhappy or being bullied then discuss this with your doctor at your next clinic visit. Your doctor may consider arranging for your child to be seen by a skin specialist (dermatologist) for more intensive treatment. This has only been necessary in a few cases.

E. Treatments

1.Treatment you can get from your pharmacist or GP

Topical salicylic acid preparations

These are suitable for warts on the hands and feet, and many commercial preparations are available. Check with your chemist. The area is softened by soaking in warm water for 5-10 minutes before use. Dead skin can be removed with an emery board or wart file. The treatment is applied directly to the wart avoiding surrounding skin. Treatment is reapplied every day for up to 12 weeks or until the wart has gone.


Freezing warts with liquid nitrogen is widely practised by GPs, dermatologists and podiatrists. Multiple treatments at 2-4 weekly intervals may be needed. This treatment is commonly used for facial warts as well as hands and feet.

Silver duct tape

This DIY tape has been shown to get rid of warts in some patients. You can buy it from DIY shops. The wart is covered with duct tape for 6 days (reapplied if it falls off). The tape is removed and the area soaked in warm water and hard skin rubbed off. A fresh piece of duct tape is applied and treatment continued for up to 12 weeks or until wart is gone.

2. Treatment that may be used by a Dermatologist

Antiviral soaks or cream

Formaldehyde solution can be used to soak the area for 15-30 minutes each day. This is most suitable for warts which cover big areas on the feet.

In very severe cases, a treatment called cidofovir 1% cream has been specially made up to treat warts. It is not licensed to be used for warts but reports in the medical literature suggest it can be effective. It has to be applied once daily for 8 weeks under a plaster. Cidofovir can damage the kidneys so blood tests have to be checked every 2 weeks during treatment.

Removal under a local anaesthetic

Warts can be removed by curettage (scraping off). This procedure is not often carried out, because all surgical procedures leave scarring, and warts may recur.

Warts can persist for longer in patients with kidney disease so don’t be afraid to mention any problems to the doctor or nurse in the clinic.

Further information can be found at:


Lunn A. Ravenscroft J. Watson AR - Cutaneous warts in children before and after renal transplantation.
Paed Nephrol 2010.

Content compiled by members of the Children’s Renal & Urology Unit, QMC Campus, Nottingham University Hospitals.

The National Kidney Federation cannot accept responsibility for information provided. The above is for guidance only. Patients are advised to seek further information from their own doctor.