|  | Conditions & Treatments | Warts

Warts: Causes, Types, Transmission, and Prevention

What Are Warts?

Warts are benign skin growths caused by an infection of the epidermis with human papillomavirus (HPV). More than 100 HPV types exist, and different types lead to distinct wart presentations.

Common Types of Warts

  • Common warts (verruca vulgaris): Rough, raised, gray-brown lesions typically found on hands, fingers, and knees. Associated with HPV types 2 and 4.
  • Plantar warts: Located on the soles of the feet; they grow inward due to pressure, causing pain and often showing black dots (thrombosed capillaries). Linked to HPV 1, 2, and 4.
  • Flat warts (verruca plana): Small, smooth, flat-topped papules commonly appearing on the face, legs, and shaving sites. Associated with HPV 3 and 10.
  • Filiform warts: Thread-like projections often seen on the face, eyelids, and lips. Caused by HPV 1 and 2.
  • Genital warts (condyloma acuminata): Sexually transmitted; low-risk types (HPV 6, 11) cause most genital warts, while high-risk types (HPV 16, 18) are linked to cancer.

Transmission

  • Direct skin-to-skin contact with an infected person.
  • Autoinoculation: touching a wart and then another part of your own body.
  • Fomites: contaminated surfaces such as floors, towels, razors, and nail tools—the virus survives only briefly outside the body.
  • Sexual contact (for genital warts).
  • Incubation period ranges from 1 to 6 months, but can extend to years.

Treatment Options

  • Over-the-counter (OTC): Salicylic acid (17–40%) acts as a keratolytic; requires weeks of daily use. OTC cryotherapy kits are less effective than clinical treatment.
  • In-office procedures: Liquid nitrogen cryotherapy (gold standard), cantharidin, candida antigen immunotherapy, pulsed dye laser, and surgical excision.
  • Prescription topicals: Imiquimod, 5-fluorouracil (5-FU), tretinoin.
  • Genital warts: Podofilox, sinecatechins, trichloroacetic acid (TCA), or provider-applied therapies.

Prevention

  • HPV vaccination (Gardasil 9) prevents nine high- and low-risk HPV types; recommended for ages 9–26.
  • Avoid touching or picking warts; wash hands after contact.
  • Do not share personal items (towels, razors, socks, shoes).
  • Wear flip-flops in locker rooms, pools, and communal showers.
  • Keep skin intact—moisturize regularly and cover cuts.

Most warts resolve spontaneously within 1–2 years due to immune clearance. Treatment is warranted if warts are painful, spreading, cosmetically bothersome, or genital.

Warts - Related Articles