Plantar (Foot) Warts

Close up of Plantar Wart.  Notice the slight speckling and disruption of normal skin lines.

Close up of Plantar Wart. Notice the slight speckling and disruption of normal skin lines.

Plantar warts—Plantar warts, or often called plantar verrucae, are skin lesions caused by infections of a papillomavirus or HPV.  There are many types of HPV but types 1 and 2 are the usual causes of warts on the feet.  They are more common in children and adolescents and will often run their course and resolve spontaneously after several weeks or months.  Sometimes they are slower to resolve or tend to be chronic.  They can also appear in adults and are a frequent reasons someone may seek out care from a podiatrist or foot doctor.  They are usually painless but can cause significant pain when located on areas of high pressure, particularly the heel or ball of the foot.

Are warts serious?

In the average healthy person, plantar warts can cause some pain if under a high pressure area but are not life threatening or medical emergencies.  In severe or highly chronic cases they can turn cancerous.  Also be aware that sometimes what looks like a wart may not actually be a wart, so you should have any suspicious lesion evaluated by an appropriate health care professional.

Why do warts occur?

Given warts are caused by a tiny virus, they develop after exposure to that virus.  Surfaces such as locker room or gym floors, swimming pools, or any other area that could come in contact with someone’s bare feet can be a potential source of transmission.  Although many of us come in contact with the virus, only some of us get warts and the specific reasons are still unknown.  It may have to do with our own genetic makeup as well as the health of our immune systems.   In either case, they are very common and nothing to be ashamed of.

Why are warts difficult to cure?

Warts can be difficult to cure and this fact needs to be understood prior to beginning any wart treatment.  The virus can lay dormant in the deep cells of the skin even after the visible wart has resolved or been destroyed….thus recurrence is a possibility.

Is there anything I can do at home to get rid of a wart on my foot?

There are many types of “over the counter” medicines that are aimed at treating warts.  The most common treatments contain an acid such as salicylic acid or other chemical that is intended to eat away and dry out the lesions, thus killing the cells that contain the virus.  There are also home freezing remedies which attempt a localized freezing destruction of skin and virus.  These treatments can sometimes be effective or offer some relief or reduction in size of the wart.   If you try a home remedy make sure you follow the directions and seek medical attention for any complications.

What be done to treat warts?

Topical Medications

Sometimes we’ll recommend an over the counter treatment or other prescription medication to be applied topically to the wart.  These usually require daily application and for some people are an easy and effective treatment.  Often people have already tried “off the shelf” treatments before they come to see us.  If so, we’ll typicall recommend one of the treatments below or perhaps a prescription strength medication such as 5 Flourouricil or Efudex which are used “off-label” for treatment of foot warts, have been shown in studies to be effective.

The Cryoprobe uses a very fine stream of nitrous oxide to freeze a wart or other lesion.The Cryoprobe uses a very fine stream of nitrous oxide to freeze a wart or other lesion.

Cryotherapy – Freezing a Wart

A “Cryoprobe” is a device that allows us to deliver a very fine and very precise jet of –127 degrees Fahrenheit nitrous oxide at 725 pounds per square inch with a predictable degree of skin penetration.  Application is generally tolerated well although there may be some tenderness and development of a small blister several days there after.  This area of dead skin may eventually just slough off and typically leaves no scar.  This treatment is great for kids or adults who prefer minimizing pain without use of anesthesia.  This same tool can also be used for other small skin lesions such as moles or nevi, skin tags, age spots, molluscum contagiosum and porokeratomas.

Cantharone – Chemical containing Cantharidin, blistering agent

Cantharone is a chemical harvested from species of blister beetles.  These beetles make a chemical called cantharidin which causes a blister when bitten.  We can apply a commercial compound called cantharone as a nice option to treat a plantar wart.  It is painlessly applied to a wart in our office and then over the next couple days may result in the formation of a blister of the skin.  This can cause some discomfort with walking for a day or two but usually feels better by day 3.  Sometimes there is no pain at all and a minimal blister forms.  A good reaction to the medication will result in a nice skin blister in the area of the wart which causes the wart to separate off the skin where it then dies and can be painlessly trimmed away about 7-14 days after application.  I have seen warts separate off after one treatment however a typical persistent plantar wart will take between 1-3 treatments.

Biopsy and Electro or Chemical dessication/destruction

This procedure involves using local anesthetic to numb up the area of the wart followed by excising the lesion which can then be sent to pathology for identification.  The base of the lesion is typically treated with an acid to destroy any remaining skin cells that may contain the virus, or carefully burned using a device that puts out an electrical current.  This is the fastest way to remove a wart.  It allows for the specimen to be sent to a pathologist to evaluate and identify the lesion.  Recurrence is still possible but perhaps less likely.  The downside is that it is also the most invasive technique.  We usually reserve this treatment for people who have failed other less invasive treatments.  Sometimes when warts are too large or there are too many to treat in the office this procedure will be done in an outpatient surgery setting under local IV sedation.

What are the risks?

Risks are variable depending on what procedure is chosen to treat a wart.  With treatments such as freezing, Cantharone, and surgical excision there are risks of developing a wound which may take some time to heal.  There is risk of infection.  There is risk of some tenderness, pain, swelling, reaction to medication or anesthetic, risk of scar tissue, and of course one must never forget risk of recurrence or regrowth of the wart.  Remember, warts can be very challenging to treat.  If you’re going to undergo any one of these particular procedures, we will review the specific risks with you so you can make an informed decision.

What is the prognosis?

For most people the prognosis for most plantar warts is quite good.  On occasion someone will bring in a small child for evaluation of a recently discovered foot wart.  As long as it is not limiting the patient or causing any pain it is reasonable to give these a few weeks or months to resolve on their own. When warts are causing pain or difficulty walking treatment is a reasonable option.  Although sometimes challenging, after a few visits we can usually reduce the discomfort and resolve the problem.

If you have any further questions regarding treatment of warts, or you would like an evaluation, please give us a call to schedule an appointment.