The information in this section has been gathered from existing peer-reviewed and other literature and has been reviewed by expert dermatologists on the CSPA Medical Advisory Board.

Warts are small growths on the skin caused by the human papillomavirus (HPV). This virus invades skin cells and enters a resting period, called latency, that may last for months or years. During latency, the virus multiplies and invades additional cells, which then take on the appearance of warts. Although over 100 strains of HPV can infect any part of the body, certain strains tend to infect specific areas of the skin. There are six primary types of warts:

  • Common
  • Plantar
  • Flat
  • Filiform
  • Periungual
  • Genital

Warts are contagious and can spread through direct and indirect contact. Common warts are spread through activities such as nail-biting, whereas plantar warts are often picked up from wet surfaces, such as shower stall floors and swimming pool decks. Flat warts are usually spread by shaving, and genital warts, which are highly contagious, are spread through sexual activity.

HPV infections can sometimes occur along with other uncommon disorders, such as epithelial hyperplasia (Heck’s disease), epidermodysplasia verruciformis or plantar cysts. Some strains of genital warts have the potential to cause cancer of the cervix, vulva, penis and anus.

Although warts frequently recur after treatment, many will disappear spontaneously within two to three years.

Fast Facts

Non-genital warts:

  • Approximately 65 per cent of non-genital warts disappear without treatment within two to three years.
  • Approximately 7 to 12 per cent of the general population is affected by warts.
  • Warts are more common in children. Approximately 10 to 20 per cent of school-aged children are affected.
  • In children, the incidence of warts peaks at 12 to 16 years of age.
  • Warts are twice as frequent in Caucasians as in those of African or Asian descent.
  • Both men and women are equally affected by warts. Up to 50 per cent of all men and women have been infected by HPV at some point in their lives.

Genital warts:

  • Genital warts are considered the most common sexually transmitted disease, affecting approximately 1 per cent of the population.
  • Both men and women are equally susceptible to infection.
  • Genital warts are most common in individuals aged 17 to 33 years of age.
  • It is estimated that 75 per cent of sexually active men and women will experience at least one genital HPV infection in their life.


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