Causes
Plantar warts are caused by a common virus called HPV, or human papillomavirus, which usually enters your body through a cut or sore on the foot. Like other viruses, this strain of HPV is contagious, and can often be contracted by contact with an infected source.
Plantar warts are not considered a serious condition, and treatment is not required as many go away on their own eventually.
Treatments
Although treatment is not necessary, you can find relief from the discomfort or embarrassment of plantar warts through over-the-counter treatments or by consulting with your primary care physician. Common methods include treating the affected area with a gentle acid, like salicylic acid. These acids help to slough off older skin, wearing down the layers of the wart.
Your doctor may also treat stubborn plantar warts with liquid nitrogen. Applying duct tape to the area like a bandage has also shown to be an effective remedy. In more serious instances, your doctor may surgically remove the wart.