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Latest update 31/08/2010
This chapter is set out as follows:
Aetiology
- Warts are growths of the skin caused by infection with the Human Papillomavirus (HPV). More than 70 HPV subtypes are known
- Infection occurs by direct or indirect contact
- A damaged epithelial barrier greatly increases the risk of inoculation:
- Plantar warts transmitted from swimming pools due to the rough surfaces abrading the skin of the feet
- Periungual warts in patients who bite their finger nails
- Shaving spreads warts over the beard area
- New warts may develop along the sites of trauma, this is known as the Koebner phenomenon
- The incubation period ranges from a few weeks to over a year
Prevention
- Warts are contagious but the risk of transmission is low
- Children with warts should NOT be excluded from physical activities, but should take care to minimise transmission
- Cover the wart with a waterproof plaster when swimming
- Wear flip-flops in communal showers
- Avoid sharing shoes, socks and towels
- Limit personal spread by
- Avoiding scratching lesions
- Avoiding biting nails or sucking fingers that have warts
- Keeping feet dry and changing socks daily
Management of warts (excluding anogenital warts)
- Patient information leaflet on plantar warts
- No treatment - this is always an option if the warts are not causing any problems. The natural history of warts should also be considered. Up to 90% of warts in young children will resolve in two years. However warts in adults, those with a long history of infection and in immunosuppressed patients are less likely to resolve spontaneously and are more recalcitrant to treatment
- Pairing of warts - the discomfort caused by warts results from thickened skin. Pairing of warts reduces discomfort and helps improve the efficacy of the treatments dicussed below.The technique for pairing is as follows
- Soak in warm water for 5-10 minutes
- Pair away the dead skin using a disposable emery board / nail file
- Perform once to twice a week
- Duct tape - the wart is occluded with duct tape for six days after which time the wart should be soaked in warm water for five minutes and paired down. The wart is then left uncovered overnight and the duct tape put on the next day for a further six days. This should be continued until the wart resolves
- Salicyclic acid - there are various lotions, paints and special plasters available over the counter. These should be used every night for at least three months. As with other treatments it is important to make sure that warts are regularly paired down. An alte rnative to salicylic acid is gluteraldehyde. Topical treatment are best avoided on the face due to the risk of irritation and scarring
- Cryotherapy - see notes below - inbetween treatments of liquid nitrogen the use of other treatment modalities such as duct tape or salicyclic acid may be of additional benefit
- Formaldehyde solution - this can be useful for plantar warts. It is prescribed as a 4 or 5 % solution and used OD for 6 weeks. Please refer to the 'patient information leaflet' section of the website for more information on how to use the treatment. Note that the price of formaldehyde solution varies substantially between different pharmacies - this may be worth discussing with your PCT pharmacy advisor
- Curettage and cautery - can be useful for filiform warts, especially on the face. It can also be used for other warts that have failed to respond to other treatments. The main problem with this technique is that recurrence rates are up to 30%
- Laser therapy - has been used with some success in warts unresponsive to other treatments
- Other treatments - small studies have shown a number of other treatments to be of benefit in some patients. These treatments are off-label but appear to be safe (see notes on the use of off-label treatments on the website)
- Efudix ® cream (5-FU cream) - applied once a day at night under occlusion. Wash the hand thoroughly that was used to apply the cream. Wash the treated area the following morning. Review after four weeks
- Aldara ® cream (5% imiquimod cream) - may help in immunocompromised patients. Apply three nights a week (e.g. monday, wednesday, friday) until the wart resolves. Wash off the following morning
- Topical retinoids applied once to twice a day
- Oral cimetidine
Liquid nitrogen
- Liquid nitrogen is used to treat numerous conditions such as warts, seborrhoeic keratoses and actinic keratoses. Treatment must only be given if the lesion can confidently be diagnosed as benign, if not a biopsy is required for histological purposes
- Liquid nitrogen should be avoided on the gaiter area of legs in older patients and others at risk of leg ulcers. It should also be avoided on distal extremities in patients with Raynaud's syndrome, peripheral vascular disease and peripheral neuropathy
- Provide a patient information leaflet
- Their are several ways of administering liquid nitrogen
- Cryogun (spray / probe) - is the most effective
- Cotton bud technique - the cotton bud is dipped in to liquid nitrogen and then applied on to the skin. The destructive energy released by this technique is substantially less than with the cryogun, but can be useful especially in younger patients and in areas such as the face where careful application is important. Cotton buds should not be placed directly in to containers of liquid nitrogen as the virus can survive in liquid nitorgen and may be passed on to other patients
- Histofreeze canisters - theorectically avoid the need for storage of liquid nitrogen HOWEVER as with the cotton bud technique the energy released is much less. Neither histofreeze or cotton buds are likely to be successful on plantar and other stubborn warts
Technique
- Pair down lesions
- If using a cryogun hold the tip approximatley 5 mm away from skin
- Spray until the wart and 2 mm of normal surrounding skin have gone white and then continue to keep topping up the liquid nitogen so the area rema ins white for the appropriate freeze time
- Freeze times are counted from when the target area goes white
- Using a guard - is particularly important when treating warts on the face. Auroscope pieces can be used for this purpose or specific plastic guards can be purchased
Freeze times
- A single 15-30 second freeze is adequate for most warts. For troublesome plantar warts a double freeze-thaw cycle has been shown to improve clearance rates
- Shorter freeze times (10-15 secs) are preferable on the face and fingers
- Repeat treatment every two-three weeks, leaving greater intervals between treatments may reduce efficacy
- The application of topical salicyclic acid preparations in between treatments may improve efficacy
Adverse effetcs
- Blistering
- Pain for up to 48 hours afterwards
- Post inflammatory hypo / hyperpigmentation, particularly in darker skin - one has to very wary of using liquid nitogen on cosmetically sensitive areas in darker skinned patients
- Treatment around nail folds occasionally causes permanent nail dystrophy and so shorter freeze times should be used
- Damage to tendons with eventual rupture can occur, albeit rarely, to the extensor tendons of the fingers. The highest risk areas are the dorsal aspects of the MCP and DIP joints. Again shorter freeze times are recommended
- Leg ulceration - most commonly arises in the gaiter area of the lower leg
- Occasional hair loss in the beard area
For more information on liquid nitrogen please refer to the Skin Surgery Guidelines on the surgical section of the website
Types of warts
Common wart
- Mainly due to HPV 2
- Present as firm papules with a rough surface
- Most commonly found on the backs of the hands and fingers but can occur anywhere
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Figure 1 - Common wart
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Figure 2 - Periungual warts (common warts around the nail)
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Figure 3 - Common wart affecting the nostril
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Figure 4 - Wart behind knee
This lesion developed in an elderly patient. The lesion was curetted and sent for histology to be on the safe side
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Plantar wart
- Most plantar warts are found beneath pressure points
- Their are two main types
- Sharply defined rounded lesions with a rough keratotic surface, often painful
- Mosaic warts, which result from a plaque of closely grouped warts and tend not to be painful
- Plantar warts can be confused with callosities or corns. Sometimes the two appear together. Callosities have a smooth surface in which the skin markings are maintained. Warts do not maintain the skin markings and when paired small bleeding points become evident. It is also said that warts are more painful when pinched, whereas callosties are more painful on pressure
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Figure 1 - Plantar warts
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Figure 2 - Mosaic warts
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Plane wart
- The face and backs of hands are the most common sites, lesions are often numerous
- Lesions are often small (under 5 mm), round, slightly elevated and have a smooth surface
- Koebnerisation is relatively common
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Figure 1 - Plane warts affecting the face
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Figure 2 - Plane warts affecting the face
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Filiform wart
- These are most commonly found on the face and neck in men, but they can occur on any part of the body
- They have a filiform appearance and may have a stalk
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Figure 1 - Filiform wart of the cheek
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Anogenital wart
- Usually multiple
- Lesions are soft, pink, elongated and sometimes filiform or pedunculated
- May cause discomfort, discharge or bleed
- Predispose to cervical, penile and vulval cancer
- Anogenital warts are uncommon in children and there presence raises the possibility of sexual abuse. The possibility of non-sexual transmission is more likely if
- There are no other suspicious features
- The warts are located on fully keratinised skin as opposed to the genital or anal mucosa
- Their is a clinical resemblance to common warts
- The child is very young, perhaps up to 2 years old – in such cases the warts may have been transmitted at birth from the mothers genital tract
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Figure 1 - Anogential warts
(copied with kind permission from Dermatoweb)
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