What are warts?

Warts are skin growths caused by the human papillomavirus (HPV). There are different strains of the virus, with each strain infecting a preferred area of the body. The name of the wart depends on the location of the body affected and the appearance of the wart.

How do you get warts?

The human papillomavirus gains access into the skin typically through minor abrasions or cuts. The virus is picked up by direct contact with a contaminated surface (i.e. floors, gym equipment, etc.) or via skin-to-skin contact with an infected person. Autoinnoculation occurs when an individual with a wart spreads the virus to adjacent healthy skin. This explains why often times more than one wart is present.

How are warts treated?

To date there is no antiviral therapy to cure HPV infections. Typically a combination of therapies applied over several months are needed to clear the warts. Patient compliance is key in order to achieve clearance. Destructive therapies with or without immune system stimulating or cytotoxic agents are used to kill the cells containing human papillomavirus. Since warts are otherwise benign growths, the goal is to avoid overly aggressive therapies that can result in permanent scarring. There is no evidence to support that aggressive treatment results in a better long-term outcome. Below are some of the therapies your physician may recommend:

  • Destructive: cryotherapy, cantharidin solution, salicylic acid solution or tape
  • Cytotoxic: 5-fluorouracil, podophyllotoxin solution, bleomycin injections
  • Immune-Stimulating/Antiviral: imiquimod cream, candida injections, cidofovir gel

Why does it take so long to treat warts?

Normally it takes several months, sometimes a few years to clear warts. There are a few reasons why it takes so long:

  • Warts are thick and will continue to grow until completely cleared. Compliance and persistence are essential with repeated application of in-office and at-home therapies to shrink the wart and get to the root of where the virus is residing. Any lapse or pause in treatment will allow the wart to grow back to its original size. ONE TREATMENT IS NOT ENOUGH.
  • The human papillomavirus has evolved to evade the immune response. The virus does not have a viremic phase and can remain undetected by the immune system.
  • HPV particles have been detected in normal skin adjacent to the warts. Therefore, once the warts are visibly cleared, it is not uncommon for the warts to later recur.

Are over-the-counter freezing therapies just as effective as liquid nitrogen?

No they are not. Over-the-counter freezing therapies which are composed of liquid dimethyl ether and propane reach a maximum low temperature of -42⁰C. Liquid nitrogen which is used in the physician’s office reaches a lower temperature of -196⁰C, allowing for deeper freezing of the wart.