Plantar warts (sometimes mistakenly called "planter’s warts") are warts that occur on the bottom of the foot, known medically as the "plantar surface." Almost anyone can get a plantar wart, but they most often affect children and young adults.
They are caused by the human papillomavirus (HPV), which infects the epidermis, or upper layer of skin. Although plantar warts do not grow beyond the depth of the skin, they can be irritating and sometimes painful due to their location on the weight-bearing surface of the foot.
Similar in appearance to a corn or callus, plantar warts have a circular shape that can vary from a pinpoint to a few centimeters in size. They typically have a thick layer of callused skin on the surface. In fact, it is not uncommon for a patient to come to a podiatrist thinking he or she has a corn, only to learn that the lesion is actually a wart. Warts have characteristic "black dots," which are enlarged capillaries that are best seen when the wart has been trimmed down.
Some Facts about Plantar Warts:
- The virus that causes a plantar wart thrives in moist environments, such as a bathroom floor or shoe. If you happen to have an area of open skin, even the smallest wound, that is where the wart virus can enter.
- Feet that sweat heavily or are overly exposed to moist environments are more at risk for developing warts.
- In some cases, warts can go away on their own. However, they may also increase in size or number if left untreated. The amount of time it takes to eliminate a wart depends on the treatment and the size and depth of the wart. Generally, the more aggressive the wart treatment, the faster the wart will resolve.
There are a variety of over-the-counter (OTC) wart treatments, most of which contain salicylic acid, which is applied topically as a liquid or in bandage form. A canned freezing spray treatment is also available. The success of any of these treatments depends on the size of the wart and how consistently the treatment is used. Some warts may not be eliminated, which can cause frustration.
The "duct-tape method" created a stir a few years ago as an unconventional yet effective method for eliminating a wart. This method involves repeated applications of duct tape to the wart for a few days and then removing the tape and the dead skin created by it. Further research now shows this treatment probably won't work.
If you decide to try an OTC salicylic acid treatment or the duct tape method, apply the treatments consistently and slough or file away dead skin between treatments to increase effectiveness. This can be done using a store-bought callus file or pumice stone. Gently file away dead skin, which will have a white appearance. Not all dead skin skin may slough away, so stop filing if the area become irritated or painful.
Having a wart treated by a podiatrist or other physician will involve more effective methods of treatment. First, the lesion will be pared or trimmed down, making it easier to target the actual wart. Some common medical wart treatments options include:
- Liquid nitrogen, or cryotherapy. This freezes the lesion and causes the skin to slough off. This may require more than one treatment, but is generally quite safe to do under a doctor's care.
- Prescription-strength acids or other topical medications. Like cryotherapy, these methods cause a sloughing of skin and sometimes require repeated treatments depending on the wart size.
- Surgical removal of the lesion under local anesthesia. This method removes the wart in one treatment, but requires the lesion to be numbed with an injection of a local anesthesia medicine.
Dockery, DPM, Gary L. and Crawford, DPM, Mary Elizabeth (Ed.). “Viral Skin Infections.” Cutaneous Disorders of the Lower Extremity. Philadelphia: W.B. Saunders, 1997.71-77.