Plantar Warts: Information & Plantar Wart Specialists

Two different types of warts commonly occur on the soles of the feet:

• Common warts (Verrucae vulgares),
• plantar warts (Verrucae plantares), also known as plantar warts.

Plantar warts are further classified into

• mosaic warts and
• spike warts.

Mosaic warts appear as a scattered cluster on the soles of the feet or the balls of the feet. They are about the size of a pinhead and whitish in color. Initially, they appear individually. However, they can multiply over time and grow together on the surface to form clusters of plantar warts.

Plantar spurs occur individually and grow deep into the tissue. They typically form on areas of the sole that are subject to particular pressure. The undersides of the toes are also frequently affected.

This type of plantar wart is often covered by calluses. They can develop a central, spike-like keratinous cone. Especially in the heel area, they can grow very large and extend all the way to the periosteum.

In general, warts occur in about ten percent of adults and children.

Plantar warts are highly contagious, making them a well-known and common phenomenon in dermatology (skin medicine).

All types of warts are caused by viruses. Most commonly, these are human papillomaviruses (HPV). There are over 100 different types of HPV.

Transmission occurs from person to person through contact with infected skin flakes. These can be found, for example, on the floor or in shared footwear, such as in

• swimming pools,
• gyms,
• locker rooms, or
• sauna facilities.

Warm, moist, and swollen skin makes it even easier for the viruses to penetrate skin cells. The locations mentioned above are ideal for this.

The viruses enter the outermost layer of the skin (epidermis) through small breaks in the skin or mucous membranes. There, they multiply in the cell nuclei, causing the characteristic wart growths to form.

After infection with papillomaviruses, it can take several months for plantar warts to form. However, plantar warts are not known to spread through the bloodstream.

Plantar warts are often hidden beneath a callus and are therefore well concealed. They cause pain when walking or when pressure is applied to the affected area.

This type of plantar wart generally consists of a grainy, whitish mass. It is surrounded by a thickened ring. A distinct groove is usually visible between the thickened callus ring and the actual wart. Another characteristic of these plantar warts is the presence of numerous brown to black dots or streaks. These are caused by bleeding from fine blood vessels into the wart.

Mosaic warts are the second type of plantar wart. They grow only on the surface—that is, not into the skin—and usually appear in large numbers. Mosaic warts can merge with one another, forming clusters of warts. Their color is typically whitish. They do not cause pain, but they may be noticeable due to itching or a sensation of pressure.

Mosaic warts often form clusters consisting of several warts © HASPhotos | AdobeStock

Common warts are not actually plantar warts. However, they can still appear on the sole of the foot. Their surface is furrowed, like a cauliflower. Common warts can grow to be the size of a pea. They are white, gray, or brown in color. Generally, like mosaic warts, they do not cause pain, but at most a sensation of itching.

In some cases, plantar warts look relatively similar to what are known as corns. Corns are an excess of calloused skin at pressure points on or under the feet. They are not caused by a viral infection.

In rare cases, the growth may be a form of skin cancer or cutaneous tuberculosis. If you are unsure, you should therefore always have any such skin changes examined by a doctor.

Due to the characteristics of plantar warts, dermatologists can usually make a visual diagnosis. This means that they examine the affected areas and immediately recognize what the condition is.

Talking with the patient also helps to better understand the condition at hand.

Plantar warts often heal spontaneously on their own. In such cases, the body’s immune system recognizes the viruses and fights them off. As the warts heal, they slowly dry out.

In general, however, the likelihood of a recurrence (return) of plantar warts is relatively high.

If plantar warts do not heal on their own, treatment can often last for years. In many cases, the treatment proves to be unsatisfactory.

Most often, plantar warts are treated with various topical treatments. However, there are few meaningful studies on their effectiveness.

There is no direct treatment available for the viruses that cause plantar warts.

Never cut open or cut off a wart. This could cause the virus to spread and lead to further infection.

Topical Treatment of Plantar Warts

Salicylic acid is a generally effective treatment for warts. For plantar warts, a salicylic acid patch is used as part of local treatment. The salicylic acid is intended to trigger an inflammatory response in the affected tissue, leading to the healing of the plantar warts.

Treatment can take several weeks. When carried out consistently, it is successful in 20 to 40% of cases.

Plantar warts are also often treated topically with caustic agents such as

• silver nitrate,
• monochloroacetic acid, or
• trichloroacetic acid

. These caustic agents destroy the tissue affected by plantar warts, but they also damage healthy tissue around the edges of the warts. Under certain circumstances, this can cause pain when walking.

Plantar warts can also be treated with special ointments. Their active ingredients are designed to inhibit cell division in the affected skin cells and thus prevent the viruses causing the plantar warts from multiplying.

These creams contain cytotoxic agents such as bleomycin or podophyllin. In some cases, side effects such as skin reactions may occur.

Invasive Treatments for Plantar Warts

Plantar warts often extend deep into the tissue of the sole of the foot. In such cases, superficial, topical treatments are ineffective. However, it is possible to surgically remove a plantar wart under local anesthesia. This procedure is known as “curettage.”

With this method, however, healing can take a very long time, especially with deep-seated warts. In addition, severe postoperative pain and bleeding may occur.

Even with surgical removal, there is a risk that plantar warts will recur. Unfortunately, these recurrences are particularly painful and resistant to treatment.

Consequently, in most cases, an initial attempt is made to treat the warts using less invasive methods.

Electrocoagulation, Laser Treatment, and Cryotherapy for Plantar Warts

Electrocoagulation is a procedure in which tissue is selectively cauterized using an electric current. The patient receives a local anesthetic during the procedure.

Electrocoagulation kills the cells infected by the virus. This reduces the risk of recurrence by 70%. This method is often used immediately following surgical removal of plantar warts. This, too, reduces the risk of recurrence.

This procedure may result in the formation of painful scars in the area where the plantar wart was removed.

An alternative to electrocoagulation is wart removal using a laser. Two methods are available for this:

• CO₂ laser scalpel
• Dye laser

In some cases, the CO₂ laser scalpel can cause severe post-operative pain and the formation of scar tissue.

The newer dye laser cauterizes the blood vessels in the wart tissue, causing the plantar wart to dry out. However, this is a lengthy procedure. The patient must undergo three to fifteen treatment sessions at intervals of about two weeks. The number of sessions depends on the size of the plantar warts or the wart bed.

On the other hand, the risk of recurrence is very low with this treatment. Unfortunately, this treatment is not suitable for removing plantar warts.

Cryotherapy is a treatment that uses cold. An applicator is cooled to a temperature of minus 50 °C using liquid nitrogen or a mixture of dimethyl and propane. The doctor then presses the applicator against the wart for several seconds. The extreme cold freezes the skin cells, causing the wart to die off.

The freezing method is primarily used for superficial plantar warts.

When it comes to warts, prevention is better than treatment. It is easier to prevent a wart than to get rid of it later.

There are a few simple guidelines that can reduce the risk of viral infection and wart formation.

In public

• swimming facilities,
• gyms,
• locker rooms, and
• restrooms

. This prevents you from coming into contact with the floor, which may have infected skin flakes on it. Do not share your bathing shoes with others.

Dry your feet thoroughly after swimming, using the sauna, or exercising. Disinfecting your feet can be another effective preventive measure.

Furthermore, rubbing your feet with oil-based creams makes it harder for an infection to occur. The viruses then cannot penetrate the skin as easily and cause plantar warts.