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Warts and verrucae - Management
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What advice should I give to someone with warts or verrucae?
- Although warts can be cosmetically unsightly, they are not harmful; usually they do not cause symptoms, and resolve without treatment.
- Warts are contagious, but the risk of transmission is thought to be low.
- To reduce the risk of transmission:
- Cover the wart with a waterproof plaster when swimming.
- Wear flip-flops in communal showers.
- Avoid sharing shoes, socks, or towels.
- Limit personal spread (auto-inoculation) by:
- Avoiding scratching lesions.
- Avoiding biting nails or sucking fingers that have warts.
- Keeping feet dry and changing socks daily.
- Children with warts or verrucae should not be excluded from activities such as sports and swimming, but should take measures to minimize transmission.
Basis for recommendation
These recommendations are based on expert opinion published in guidelines from the British Association of Dermatologists [Sterling et al, 2001] and the Health Protection Agency [HPA, 2008].
Should warts and verrucae be treated?
- For most people there is a strong case for not treating warts or verrucae.
- Warts do not usually cause symptoms.
- Most warts resolve spontaneously within months or, at the most, within 2 years.
- Treatment may be prolonged and can have adverse effects.
- Cryotherapy requires several clinic visits, can be painful at the time of application, and may cause pain, blistering, infection, and depigmentation.
- Topical salicylic acid may require administration for up to 12 weeks and can cause local skin irritation.
- Consider treatment if:
- The wart is painful (for example on the soles of the feet or near the nails).
- The wart is cosmetically unsightly (for example on the hands or face).
- The person requests treatment, and the wart is persisting.
Basis for recommendation
No treatment
- The recommendation for no treatment is taken from guidelines published by the British Association of Dermatology and is based on expert opinion [Sterling et al, 2001].
Spontaneous resolution
- A cohort study (n = 1000) conducted in children found evidence that two-thirds of warts resolve spontaneously within 2 years [Massing and Epstein, 1963].
- A Cochrane systematic review pooled data from 21 trials and found evidence that the average cure rate for people receiving placebo was 27% (95% CI 0 to 73) after an average of 15 weeks [Gibbs and Harvey, 2006].
Warts that persist
Which treatments are recommended in primary care for warts or verrucae?
- Facial warts should not routinely be treated in primary care.
- For more information on referral and secondary care treatments see Referral.
- Treatment of non-facial warts:
- For adults and older children, treatment depends upon what has been tried already and individual preference. Options include:
- Topical salicylic acid (applied daily for up to 12 weeks).
- Cryotherapy with liquid nitrogen (usually carried out once every 3 or 4 weeks for up to four cycles). For information on who should not receive cryotherapy, see Contraindications for cryotherapy.
- Combination therapy with salicylic acid and cryotherapy (applying topical salicylic acid preparations between cryotherapy sessions once the scabbing from cryotherapy has resolved).
- For younger children, offer treatment with topical salicylic acid applied daily for up to 12 weeks.
- Do not use cryotherapy in younger children.
- Duct tape occlusion could also be considered, although there is limited evidence for its use.
- Adverse effects are minimal, but local skin irritation can occur and the tape may fall off.
- Over-the-counter freeze sprays, glutaraldehyde, formaldehyde, and silver nitrate are not recommended.
Contraindications for cryotherapy
- Avoid using cryotherapy for:
- People with an uncertain diagnosis or a possible malignancy.
- Young children (who may find it too painful).
- Distal extremities in people with:
- Raynaud's syndrome.
- Peripheral vascular disease.
- Peripheral neuropathy.
- Periungual sites — this is painful and there is a risk of subungual hemorrhage.
- For warts that are over tendons and near superficial nerves it is preferable to use topical salicylic acid. Cryotherapy may be considered but with shorter durations of freeze-thaw cycles.
Basis for recommendation
Salicylic acid
- There is evidence from a Cochrane systematic review, that salicylic acid administered daily for up to 12 weeks is more effective than placebo at clearing cutaneous warts, with a low likelihood of adverse effects. Limited trial data suggest that it is at least as effective as cryotherapy.
- There is insufficient evidence to recommend any particular salicylic acid preparation over another.
- Topical salicylic acid is a well-established treatment for warts.
Cryotherapy with liquid nitrogen
- There is little evidence regarding the effectiveness of cryotherapy, and in particular there is no evidence to support the common view that cryotherapy is more effective than topical salicylic acid.
- Available evidence, from a Cochrane systematic review, suggests that more intense levels of freezing (that is, a longer duration of application of cold to the wart) are more effective than gentler freezing regimens; that treatment intervals of 2, 3, or 4 weeks are equally effective; and that treatment beyond 3 months is unlikely to give any additional benefit.
- There are limited data on adverse effects, but pain and blistering are commonly reported and seem to be more likely to occur with more frequent applications and more intense levels of freezing.
Contraindications to cryotherapy
Combining salicylic acid and cryotherapy
- There is limited evidence for this approach [Gibbs and Harvey, 2006], and there is uncertainty regarding the best regimen to use when combining these treatments.
- Specialists use various approaches to alternating salicylic acid and cryotherapy, over differing timescales.
- Most CKS expert reviewers agreed that combination therapy is appropriate in primary care and that it may be useful to use the topical treatment once the scabbing from cryotherapy has resolved.
Duct tape
- There is limited evidence that occlusion with duct tape is effective for treating warts. There is weak evidence from one small randomized controlled trial (RCT) (n = 51) that occlusion with duct tape may be an effective treatment for warts. However data from two subsequently published larger trials (n = 90, n = 103) do not support this conclusion.
- Adverse effects were infrequent in adults. In one trial, 15% of children who were treated with duct tape experienced erythema, eczema, and wounds but this finding was not statistically significant.
Cryotherapy for younger children
- Cryotherapy is not recommended because younger children may find it too painful and may not be able to keep still long enough for the treatment to be applied.
Cryotherapy with over-the-counter freeze spray
- There is weak evidence from one small (n = 124) RCT that dimethyl ether/propane (DE-P) has equivalent efficacy to liquid nitrogen for the treatment of warts [Caballero Martinez et al, 1996]. However, this trial had a number of methodological problems making the results difficult to interpret.
- There are also concerns that DE-P (which evaporates at –57°C) does not reduce the tissue temperature enough to cause adequate cell necrosis [Sterling et al, 2001], although this has not been evaluated in RCTs. In comparison, liquid nitrogen reaches a much lower temperature when it evaporates (–196°C).
Silver nitrate
- Chemical cauterization with silver nitrate has been used for decades to treat cutaneous warts, however the evidence base to support its use is very limited. There is very weak evidence from two small trials (n = 70, n = 60) that silver nitrate is effective for treating warts. Both trials had methodological weaknesses, making the results difficult to interpret. Well-conducted RCTs are needed to confirm these results.
- Silver nitrate may cause chemical burns on the surrounding skin and black discolouration of the skin.
- Most CKS expert reviewers agree that silver nitrate should not be used.
Glutaraldehyde, formaldehyde, podophyllin, and podophylotoxin
- CKS found no placebo controlled RCTs that assessed the effectiveness of glutaraldehyde, formaldehyde, podophyllin, or podophylotoxin for the treatment of warts. However they may be used in secondary care.
How should wart/verruca treatments be applied?
- Topical salicylic acid:
- Before applying, soften the area by soaking it in warm water for 5–10 minutes.
- Peel off any film remaining from the previous application.
- Avoid applying the treatment to the surrounding skin.
- Debride the surface of the wart/verruca with an emery board once or twice a week, to remove excess hard skin.
- Do not apply to the face or areas that are extensively affected because of an increased risk of skin irritation and scarring.
- Cryotherapy:
- Only practitioners who have been trained in the use of cryotherapy should carry out this treatment.
- Before performing cryotherapy, obtain informed consent and document:
- When cryotherapy is undertaken.
- The thaw times and freeze times used.
- A spray is commonly used to apply liquid nitrogen. The spray is applied until a halo of frozen tissue appears around the wart, and is then timed for 5–30 seconds depending on the site and size of the wart.
- Cotton buds may be preferable when treating children or for warts near the eyes. If cotton buds are used, to reduce the possible transmission of viruses:
- Decant liquid nitrogen into a separate disposable container (from a Dewar flask).
- Use one cotton bud for each person treated, discard left-over liquid nitrogen, and keep the Dewar flask cleaned and full.
- Duct tape:
- Cover the wart with duct tape for 6 days (if the tape falls off, apply a fresh piece).
- Remove the tape after 6 days, soak the wart in water, and gently debride with an emery board or pumice stone.
- Leave the wart uncovered overnight and reapply a fresh piece of duct tape the next day.
- Continue treatment for up to 2 months.
Basis for recommendation
When should I refer someone with warts or verrucae?
- In general, warts can be managed in primary care, however a number of specialized treatments are available in secondary care.
- Refer to a dermatologist if:
- The person has a facial wart and requests treatment.
- The diagnosis is uncertain.
- There are multiple recalcitrant warts and the person is immunocompromised.
- The person has areas of skin that are extensively affected, for example mosaic warts.
- The person is bothered by persistent warts which are unresponsive to both topical salicylic acid and cryotherapy.
- The person is bothered by persistent warts which are unresponsive to topical salicylic acid and cryotherapy is contraindicated.
- For those people with diabetes and a verruca — refer to diabetic foot services for management.
Treatment options in secondary care
- Treatment options available in secondary care include:
- Physical ablation, such as surgery, laser treatment, and photodynamic treatment.
- Antimitotic treatments, such as topical podophyllotoxin, topical or oral retinoids, or intralesional bleomycin.
- Immunomodulatory treatments, such as topical sensitizers (dinitrochlorobenzene, diphencyprone, or squaric acid dibutylester), topical imiquimod 5%, or intralesional interferon.
- Virucidal treatments, such as formaldehyde and glutaraldehyde.
- Cantharadin (a potent blistering agent extracted from blister beetles) may be available in some secondary-care departments.
Basis for recommendation
Referral criteria will ultimately depend upon local recommendations. The suggested referral criteria are based on expert opinion in guidelines published by the British Association of Dermatologists [Sterling et al, 2001], and widely accepted good clinical practice.
- Facial warts should not be treated in primary care with topical salicylic acid (which is unlicensed for this indication) or cryotherapy with liquid nitrogen, because of the risk of severe irritation and possible scarring.
Prescriptions
For information on contraindications, cautions, drug interactions, and adverse effects, see the electronic Medicines Compendium (eMC) (http://emc.medicines.org.uk), or the British National Formulary (BNF) (www.bnf.org).
Topical salicylic acid - any site (except face)
Age from 1 year onwards
Salicylic acid 12% gel (Bazuka®)
Bazuka gel
Apply to the wart or verruca once a day.
Supply 5 grams.
Salicylic acid 12% gel (Salatac®)
Salatac gel
Apply to the wart or verruca once a day.
Supply 8 grams.
Salicylic acid 16.7% paint (Salactol®)
Salactol paint
Apply to the wart or verruca once a day.
Supply 10 ml.
Salicylic acid 26% gel (Bazuka Extra Strength®)
Bazuka Extra Strength 26% gel
Apply to the wart or verruca once a day.
Supply 5 grams.
Salicylic acid 26% solution (Occlusal®)
Occlusal 26% solution
Apply to the wart or verruca once a day.
Supply 10 ml.
Age from 6 years onwards
Salicylic acid 17% paint (Compound W®)
Compound W 17% wart remover paint
Apply to the wart or verruca once a day.
Supply 6 ml.
Topical salicylic acid - hands or feet only
Age from 2 years onwards
Salicylic acid 16.7% paint (Duofilm®)
Duofilm paint
Apply to the wart or verruca once a day.
Supply 15 ml.
High-strength topical salicylic acid - feet only
Age from 6 years onwards
Salicylic acid 50% ointment (Verrugon®)
Verrugon complete 50% ointment
Apply to the wart or verruca once a day.
Supply 6 grams.
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