Viral warts

Published on 18/03/2015 by admin

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Last modified 18/03/2015

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Viral warts

Hilmi F. Recica and Imtiaz Ahmed

Evidence Levels:  A Double-blind study  B Clinical trial ≥ 20 subjects  C Clinical trial < 20 subjects  D Series ≥ 5 subjects  E Anecdotal case reports

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Warts are a common disease caused by infection with various strains of the human papilloma virus (HPV). They appear on different sites of the body and in various forms including common, flat, filiform, periungual, plantar, mosaic, and genital warts. Children most commonly present with common or periungual warts on hands and feet, whereas adults often present with common warts on the back of hands or filiform warts on the face and neck. Genital warts are discussed in another chapter.

Management strategy

Most warts resolve spontaneously with time. However, patients and children’s parents often ask for treatment because of pain, social stigma or concern over infectivity. In some cases warts cause ridicule, distorted self-image, impaired dexterity, worry over loss of employment, or a health and safety issue. Immunosuppressed patients may have extensive and resistant warts.

Most patients will treat themselves with over the counter preparations containing keratolytics before presenting to the dermatologist. Salicylic acid has the best evidence base and is the most commonly used therapy. It can be applied in various concentrations with or without occlusion. However, it requires frequent application and it may cause irritation of the surrounding skin. Cryotherapy with dimethyl ether and propane applicator, silver nitrate pencils and occlusive ‘duct tape’ are also available over the counter.

When a dermatologist sees patients with warts, the diagnosis and the possibility of spontaneous resolution and watchful waiting should be explained. The patient should be educated on how to apply topical preparations accurately. Keeping the warts well pared down with the use of a file or pumice stone after soaking is especially important for plantar warts. Young and healthy individuals with short duration of infection have the highest clearance rate. Cryotherapy with liquid nitrogen is one of the commonest treatments used by the dermatologist. Liquid nitrogen is applied with a cryo spray or a cotton bud. The wart should be frozen outwards from the centre to include a 2 mm rim of normal skin, and the freeze maintained for 5 seconds. Cryotherapy is best repeated at 2- to 3-week intervals. Hyperkeratotic warts should be pared before cryotherapy and plantar warts treated by two freeze–thaw cycles. This treatment is painful and not always well tolerated by young children. The treated warts are sore and may blister. In pigmented skin, post-treatment hypopigmentation and hyperpigmentation can be a problem. Cryotherapy with liquid nitrogen can be combined with other topical preparations. Cryotherapy with carbon dioxide snow or dimethyl ether applicators does not produce temperatures as low as liquid nitrogen and is less effective.

If cryotherapy is not successful then various other options are available including immunotherapy with diphencyprone (DCP), squaric acid, and intralesional mumps or Candida antigen. Intralesional bleomycin may be injected into the wart or the solution applied to the wart and then repeatedly pricked through with a lancet. Laser ablation, hyperthermia, curettage and cautery or even surgical excision of troublesome and resistant warts can be attempted but the risk of scarring and recurrence of the warts in the scar can be a problem. The pulsed dye laser (PDL), thought to target the rich capillary network in warts, can be effective. Photodynamic therapy (PDT) is another option; however, pain during and after ALA (aminolevulinic acid)-PDT is well recognized. Other treatments used occasionally include 5-fluorouracil, zinc, levamisole, cimetidine, topical and oral retinoids, and imiquimod.

First–line therapies

image Salicylic acid preparations A
image Silver nitrate B
image Cryotherapy with dimethyl ether and propane C

Second-line therapy

image Cryotherapy with liquid nitrogen B

Third-line therapy

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image Bleomycin A
image Photodynamic therapy (PDT) A
image Duct tape B
image 5-Fluorouracil A
image Zinc  
 – Zinc oxide (topical) C
 – Zinc sulfate (intralesional) B
image α-Lactalbumin–oleic acid B
image Immunotherapy B
 – Diphencyprone B
 – Squaric acid C
 – Autowart C
 – Mumps and Candida antigen C
image Imiquimod C
image Pulsed dye laser C
image Pulsed dye laser with PDT C
image CO2 laser C
image Er : YAG laser C
image Intense pulsed light B
image Formic acid B
image Glycolic acid C
image Potassium hydroxide C
image Fig tree latex D
image Salicylate iontophoresis E
image Glutaraldehyde D
image Formaldehyde