I. Etiology, pathophysiology, and epidemiology

  1. Caused by Human Papillomavirus
  2. Spread by skin-to-skin contact or by fomits
  3. Peak incidence in the teenage years
  4. Immunosuppression is a risk factor

II. Classification

  1. Genital ("condylomata acuminata")
  2. Non-genital

IV. Natural history of non-genital warts

  1. One-half resolve spontaneousoly within 1y
  2. Two-thirds resolve spontaneously within 2y

III. Treatments for non-genital warts

  1. General principles
    1. Salicylic acid and cryotherapy are first-line treatments
  2. Salicylic acid
    1. Keratolytic-slowly destroys epidermis
    2. May cause an immune response as well
    3. Different preparations are available; 17% is most common
    4. 73% cure rate in 6-12wks vs. 48% with placebo in one meta-analysis (Cochrane, 2006)
    5. Combining with cryotherapy may be more effective than either alone
    6. Can cause minor skin irritation
    7. Can cause hypo- or hyperpigmentation so avoid use on the face
    8. Common protocol for use
      1. Soak wart in warm water x 5min then gently file down with pumice stone or emery board
      2. Apply salicylic acid
      3. Repeat a-b daily (if using liquid or gel) or Q2d (if using patch) until wart clears but no more than 12wks
      4. Discontinue if reach 12wks or if experience severe redness, pain, or itching
  3. Cryotherapy, e.g. with liquid nitrogen
    1. Freezes to temp of -321'F
    2. Cure rates similar to salicylic acid
    3. "Aggressive" cryotherapy (application for 10-30sec) is more effective than less aggressive apprach, but more likely to cause local reactions
    4. Two freeze-thaw cycles per application may be associated with higher clearance rates for plantar warts, but not warts elsewhere
    5. No benefit to treatment more frequent than Q2-3wks
    6. No benefit to teatment beyond 3mos
    7. Paring plantar warts before cyrotherapy is associated with increased clearance rates
    8. Combining with salicylic acid may be more effective than either alone
    9. Can cause pain, blistering, hypo- or hyperpigmentation, or tendon or nerve damage with aggressive therapy.
  4. Intralesional injection with Candida or mumps skin antigen
    1. Must confirm positive skin pretest first (0.1mL intradermal in forearm; look for local reaction)
    2. For treatment, administer 0.1-0.3 mL into the largest wart
    3. May repeat Q3-4wks up to 3 treatments total
    4. Can be effective for recalcitrant warts; can also work at warts distant to the injection
    5. May cause pruritis, pain, or skin peeling; two cases reported of pain, edema, and purple discoloration of the fingertip when injected into a subungual wart
  5. Photodynamic therapy with aminolevulinic acid (Levulan Kerstick)+ topical salicylic acid
    1. Can be effective for recalcitrant warts
    2. Aminolevulinic acid induces photo-oxidation following irradiation with visible light
  6. Imiquimod (Aldara)-Acts as an immunomodulator (has been studied more for genital than non-genital warts)
  7. Treatments with limited evidence re: effectiveness
    1. Pulsed dye laser
    2. Intralesional interferon alfa
    3. Intralesional bleomycin
    4. Canthardin
    5. Dinitrochlorobenzene
    6. Duct tape-Initial studies were promising but not borne out by subsequent studies
    7. Oral cimetidine
    8. Oral zinc sulfate
    9. Podophyllin
    10. Propolis ointment
    11. Retinods
    12. Topical garlic extract
  8. Surgical treatment with cautery or curettage-"3rd-line" treatment; sdar4ring or recurrence can occur in up to 30% of pts

(Sources include AFP 84:288-293, 2011)