• Warts are caused by the human papillomaviruses (HPV)
  • Mechanism: Localized cellular proliferation and vascular growth lead to development of skin lesions that are typically verrucous and hyperkeratotic
  • Lesions resolve spontaneously in most cases:
    • About 30% within 6 mo
    • 60–70% within 2 yr
    • 90% within 5 yr
  • Types of cutaneous warts:
    • Verrucae vulgaris (“common warts”):
      • Typically found on: Dorsum of hands, sides of fingers, and adjacent to nails
      • Usually asymptomatic
    • Verrucae plantaris (“plantar warts”):
      • Typically found on: Weight-bearing parts of sole: Heels, metatarsal heads
      • Often symptomatic and painful
      • More common in adolescents and young adults
    • Verrucae plana (“flat, juvenile warts”):
      • Typically found on light-exposed areas: Head, face, neck, legs, dorsum of hands
      • Small in size
      • Range from a few to hundreds
  • Anogenital warts:
    • Known as condyloma acuminata or venereal warts
    • Most are asymptomatic and may go unrecognized
    • HPV types 6 and 11 account for 90% of anogenital warts
NOTE: HPV types 16 and 18 account for 70% of cervical cancers


  • HPV is host-specific to humans:
    • Cause infection of epithelial tissues and mucous membranes
    • Infects the basal layer of skin or mucosa
  • There are >100 types of HPV that variably infect different body sites (i.e., HPV1 tends to infect soles of feet)
  • HPV transmission is:
    • Direct: Skin to skin, mucosa to skin, etc.
    • Indirect: Contaminated surface to skin
    • Autoinoculation: Scratching, sucking (especially in young children)
  • Incubation period can range from weeks to >1 yr; however, most common range is 2–6 mo

Pediatric Considerations
  • 10–20% of children will have warts
  • Peak incidence between 12–16 yr
  • May produce laryngeal papillomatosis in infants from viral exposure at birth
  • Must consider sexual abuse in children with anogenital warts

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