Warts are common skin growths that can occur anywhere on the body.    Common places for warts include the hands, feet and genitals.

What causes warts?

All warts are caused by an infection of the skin with one of the strains of the human papilloma virus (HPV virus).  There are over 100 strains of the HPV virus and each one has a particular affinity for a certain part of the skin or mucosa.  For example, HPV 6 and 11 are the most common causes of genital warts, while HPV types 1, 2, 27 and 57 tend to cause warts on the hands and feet.

Do Warts Have to be Treated?

Not necessarily.  The majority of warts will disappear on their own within 1-2 years.  This is particularly true in children in whom it is reasonable to wait and see if a wart will go away on its own.  Warts that are bothersome, painful or spreading should be treated.

How are Warts Treated?

There are several different ways of treating warts.  The choice of treatment will depend on a number of factors, including the location of the warts, the age of the patient, and what treatments have been tried before.  A few of the more common treatments are listed below.

Liquid Nitrogen (Cryotherapy)

The most common way in which warts are treated in a doctor's office is with liquid nitrogen.  Nitrogen is a gas that makes up most of the air we breathe.  When it is made very cold (-196 °C) it becomes a liquid.  When this liquid is applied to warts (or other skin growths), it causes a separation in the skin.  The top layer peels off within 1-3 weeks and takes all or part of the wart with it.  It is also thought that the liquid nitrogen may also stimulate the immune system to attack the wart.  

Treatments with liquid nitrogen are uncomfortable for a brief period of time.  They frequently cause blistering or scabbing which is normal.   The blisters can be popped with a sterile needle if desired.

What are some other treatments that are used for warts?

  • Salicylic acid - this is available in over-the-counter wart preparations
  • Other topical compounds such as stronger concentrations of salicylic acid may be obtained by prescription
  • Cantharone.  This is a liquid that is applied to warts in your doctor's office.  It is painless when applied and so is most often used in children.  It tends to be less effective than liquid nitrogen.
  • Bleomycin injections.  Plantar warts that do not respond to other treatments are sometimes injected with a medication called Bleomycin.  This can be quite effective but is very uncomfortable.
  • Lasers are occasionally used for warts that have not responded to the above treatments

What can you do to prevent recurrences of plantar warts?

Always wear flip-flops or shower shoes when walking or showering in places like pools, gyms or shared showers where the floor is wet.  The HPV virus tends to live much longer in wet environments and warts are frequently spread this way