Warts

Essentials of Diagnosis

• Verrucous papules anywhere on the skin or mucous membranes, usually < 1 cm in diameter

• Prolonged incubation period (average 2–18 months); spontaneous "cures" (50% at 2 years for common warts)

• "Recurrences" (new lesions) are frequent

General Considerations

• Caused by human papillomaviruses (HPVs)

• Typing of HPV lesions is not a part of standard medical evaluation except in the case of genital dysplasia

• Genital HPVs are divided into low-risk and high-risk types depending on the likelihood of their association with cervical and anal cancer

Symptoms and Signs

• There are usually no symptoms

• Tenderness on pressure occurs with plantar warts; itching occurs with anogenital warts

• Flat warts are most evident under oblique illumination

• Periungual warts may be dry, fissured, and hyperkeratotic and may resemble hangnails or other nonspecific changes

• Plantar warts resemble plantar corns or calluses

Differential Diagnosis

• Seborrheic keratosis

• Hypertrophic actinic keratoses

• Squamous cell carcinomas

• Condylomata lata of secondary syphilis

• Molluscum contagiosum

• Varicella zoster (in AIDS)

• Clinical

• Biopsy may be necessary for definitive diagnosis

Medications

For Nongenital Warts

• Liquid nitrogen

  • Apply to achieve a thaw time of 30–45 seconds

  • Two freeze-thaw cycles are given every 2–4 weeks for several visits

  • Scarring will occur if it is used incorrectly

  • May cause permanent depigmentation in darkly pigmented individuals

• Keratolytic agents and occlusion

  • Salicylic acid products may be used against common warts or plantar warts

    • They are applied, then occluded

  • Plantar warts may be treated by applying a 40% salicylic acid plaster after paring

    • The plaster may be left on for 5–6 days, then removed, the lesion pared down, and another plaster applied

  • Although it may take weeks or months to eradicate the wart, the method is safe and effective with almost no side effects

  • Chronic occlusion alone with water-impermeable tape (duct tape, adhesive tape) is less effective than cryotherapy

• Podophyllin

  • Ineffective for common warts and plantar warts

  • Contraindicated in pregnant women

• Imiquimod should not be used to treat plantar or common warts

• Immunotherapy

  • Squaric acid dibutylester may be applied in a concentration of 0.2–2% directly to the warts from once weekly to five times weekly to induce a mild contact dermatitis

  • Between 60% and 80% of warts clear over 10–20 weeks

  • Injection of Candida antigen starting at 1:50 dilution and repeated every 3–4 weeks may be similarly effective in stimulating immunologic regression of common and plantar warts

• Bleomycin

  • Dosage: diluted to 1 unit/mL, injected into common and plantar warts

  • Should be used with caution on digital warts because of the potential complications of Raynaud phenomenon, nail loss, and terminal digital necrosis

• 5-Fluorouracil 5% cream applied once or twice daily, usually with occlusion, may be applied to warts with the similar efficacy to other treatment methods

• Laser therapy

  • Can be used for recurrent warts, periungual warts, plantar warts, and genital warts

  • Should be reserved for refractory cases

  • Leaves open wounds that must fill in with granulation tissue over 4–6 weeks and is best reserved for warts resistant to other modalities

• Photodynamic therapy can be considered in refractory widespread flat warts

For Genital Warts

• Liquid nitrogen

  • First-line clinician-applied surgical treatment for genital warts

  • Applied to achieve a thaw time of 30–45 seconds

  • Two freeze-thaw cycles are given every 2–4 weeks for several visits

  • Scarring will occur if it is used incorrectly

  • May cause permanent depigmentation in pigmented individuals

• Podophyllum resin

  • The purified active component of the podophyllum resin, podofilox, is applied by the patient twice daily for 3 consecutive days a week for cycles of 4–6 weeks

  • It is less irritating and more effective than "clinician-applied" podophyllum resin

  • However, recurrence is common after discontinuation, making multiple cycles necessary

• Imiquimod

  • A 5% cream of this local interferon inducer has moderate activity in clearing external genital warts

  • Dosage: once daily on 3 alternate days per week

  • Response may be slow, with patients who eventually cleared having responses at 8 weeks (44%) or 12 weeks (69%)

  • Once cleared, about 13% have recurrences in the short term

  • In women,

    • Imiquimod has high rate of response

    • Safety profile make it treatment of choice despite its expense

  • In men,

    • Podophyllotoxin is the initial treatment of choice because of more rapid response, lower cost, and similar efficacy compared with imiquimod

    • However, imiquimod should be used for recurrences or refractory cases

• Laser therapy: For genital warts, it has not been shown that laser therapy is more effective than electrosurgical removal.

• Photodynamic therapy can be considered in refractory genital warts

Therapeutic Procedures

• Soaking warts in hot (42.2°C) water for 10–30 min daily for 6 weeks can result in involution

OPERATIVE REMOVAL

• Plantar warts may be removed by blunt dissection

• For pedunculated or large genital warts, snip biopsy (scissors) removal followed by light electrocautery is more effective than cryotherapy

Prognosis

• Development of new lesions is common

• Warts may disappear spontaneously or may be unresponsive to treatment

• Combining therapies (eg, liquid nitrogen plus immunotherapy) may improve therapeutic response

Prevention

• The use of condoms may reduce transmission of genital warts

• Administration of a vaccine against certain genital HPV types can prevent infection and reduce cervical dysplasia; it is recommended for teenagers and young adults

When to Refer

• If there is a question about the diagnosis, if recommended therapy is ineffective, or if specialized treatment is necessary