All true warts are caused by a virus. The term “plantar” refers not to a type of wart but to its location: A plantar wart can occur only on the plantar surface, which is the sole of the foot. The same virus could cause a wart on the palm of your hand; that wart would be called a palmar wart.
Human Papilloma Virus
The specific virus that causes warts is called HPV, or human papilloma virus. There are more than 100 types of HPV, according to Medline Plus. Some attack skin, while others prefer mucous membranes. Oral and genital warts are both caused by HPV. To develop a wart, you must be susceptible to the virus. You may be healthy and have a normal immune system but not have a resistance to the particular virus that is attacking your skin.
Plantar Warts
Although many of these HPV viruses can cause plantar warts, the same four that cause common warts are the most likely to cause plantar warts. According to the “British Journal of Dermatology,” these are types 1, 2, 4, and 57. Warts from the same virus type will look much different on the sole of your foot than on the top.
Symptoms
Plantar warts can become painful because of the pressure from bearing weight. Instead of being raised from the skin, they may be pushed down into it. Thickened skin called a callus can form over the plantar wart and increase the pressure. The wart may feel like a rock in your shoe.
Appearance
Plantar warts appear as a rough patch of skin with a dark center. Several can grow together, in which case they’re called mosaic warts. Close inspection may reveal brown dots. Ordinary corns and calluses may also hurt from pressure and look similar to plantar warts. Warts on other parts of the foot will be easier to identify. Warts often go away by themselves, but if you have a painful plantar wart, you’ll likely want it removed.
Treatment and Prevention
Plantar warts are best removed by a physician. Pregnant women in particular should not use over-the-counter wart remedies. Plantar warts may require several treatments and are difficult to treat yourself. Getting rid of the wart won’t get rid of the virus, so warts can recur. Avoid picking or scratching warts, which can spread them to other skin areas. You may be less likely to develop warts on your feet if you don’t go barefoot, since the virus is contagious.