Plantar warts

Overview

Plantar warts are small, rough growths that appear on the feet, typically on the balls and heels, where pressure is highest. This pressure can cause the wart to grow inward beneath a thick layer of skin (a callus). Plantar warts are caused by the Human Papillomavirus (HPV), which enters through small cuts or breaks in the skin on the soles of the feet. While most plantar warts aren’t serious and often disappear on their own, especially in children under 12, they can be treated with self-care methods or by consulting a doctor for quicker removal.

Symptoms

Signs and symptoms of plantar warts include:

• A small, rough growth on the sole of the foot, often appearing at the base of the toes, on the ball, or heel.
• Tiny black dots, which are clotted blood vessels often called wart seeds.
• On brown or black skin, the growth may appear lighter than the surrounding unaffected skin.
• A cluster of growths on the sole of the foot, known as mosaic warts.
• A growth that disrupts the normal lines and ridges of the skin on your foot.
• Pain or tenderness when walking or standing.

Consult your doctor about the growth on your foot if:

• You know that the growth is painful, bleeding, or changing in shape or color 
• You’ve tried treating the wart, but it keeps coming back
• Your pain makes it difficult for you to do daily tasks
• You also have diabetes or poor sensation in your feet
• You have a weakened immune system due to immunosuppressive medications, HIV/AIDS, or other immune system disorders
• You’re not sure if the growth is a wart.

Causes

Plantar warts are caused by an HPV infection that affects the outer layer of skin on the soles of the feet. The virus enters through tiny cuts, breaks, or vulnerable areas, leading to the formation of warts. In adults, these warts can persist for several years, while in children, they may last from a few months up to two years if left untreated.

There are around 100 different types of HPV, and the virus is quite common. However, only a few types are responsible for causing foot warts. Warts found on mucous membranes or other skin areas are usually associated with different strains of HPV.

Transmission of the virus

The immune systems of different people react differently to HPV. Warts don’t appear on everyone who comes into touch with it. Even members of the same family respond differently to the infection.

Plantar wart-causing HPV strains are not very infectious. Therefore, direct contact between individuals is difficult for the virus to propagate. However, because it prefers warm, humid environments, strolling barefoot near swimming pools or locker rooms increases your risk of contracting the virus. More warts could develop if the virus travels from the initial infection location.

Risk factors

Plantar warts can affect anyone, however they are more likely to affect:

• Children and teenagers
• Individuals with compromised immune systems
• Those with a history of plantar warts
• Those who go barefoot in public places like swimming pools and locker rooms where a wart-causing virus is prevalent.

Diagnosis

A plantar wart is usually diagnosed by a medical professional through a visual examination. They may also remove the top layer with a scalpel to look for small dots, which are clotted blood vessels. Alternatively, your doctor might take a small sample of the growth and send it to a laboratory for further analysis.

Treatment

Though it may take a year or two for youngsters and much longer for adults, the majority of plantar warts are benign and disappear on their own without therapy. Speak with your doctor if you’d like to get rid of warts sooner and self-care techniques aren’t working for you. It may be beneficial to use one or more of the following treatments:

• Freezing medicine (cryotherapy). Using a cotton swab or a spray, liquid nitrogen is applied to the wart during cryotherapy. Your healthcare professional may first numb the region because this procedure can be uncomfortable.

The freezing creates a blister around the wart, and the dead tissue peels off in about a week. Your immune system may be boosted with cryotherapy to combat viral warts. Until the wart goes away, you might need to come back to the clinic for follow-up treatments every two to three weeks.

Cryotherapy can cause pain, blisters, and long-term changes in skin tone (hypo- or hyperpigmentation), especially in those with dark or Black skin.

• Stronger peeling medicine (salicylic acid). Salicylic acid-containing prescription-strength wart medications function by gradually eliminating a wart’s layers. They might also strengthen the capacity of your immune system to combat the wart.

Your doctor will likely recommend regular application of the medicine at home, with occasional follow-up visits to the office. Using this procedure, getting rid of the wart could take weeks.

Surgical or other procedures

Should freezing medication and salicylic acid prove ineffective, your physician may recommend one or more of the subsequent therapies:

• Minor surgery. Using an electric needle, your healthcare provider removes or eliminates the wart (electrodesiccation and curettage). Your healthcare practitioner will numb your skin before beginning this procedure because it might be uncomfortable. Surgery is typically reserved for treating plantar warts only when all other options have been exhausted, due to the risk of scarring. Scarring on the bottom of the foot can result in long-term pain, sometimes lasting for years.
• Blistering medicine. Cantharidin is applied by your doctor, resulting in a blister beneath the wart. To have the dead wart snipped out, you might need to come back to the clinic in about a week.
• Immune therapy. This approach boosts your immune system to combat viral warts using drugs or treatments. Your doctor may apply a cream or solution to your warts or inject them with an antigen, which is a foreign substance. 
• Laser treatment. Pulsed-dye laser treatment cauterizes small blood vessels by sealing them through heat. The wart finally falls off when the infected tissue dies. It is necessary to repeat this process every two to four weeks. Most likely, your doctor will numb your skin initially.
• Vaccine. Although the HPV vaccine is not specifically directed against the wart viruses that cause plantar warts, it has been successfully used to treat warts.

If one plantar wart disappears after treatment but another appears in a different location, it may indicate renewed exposure to HPV.