Plantar warts are benign growths that develop on the bottom of your feet caused by direct contact with the human papilloma virus (HPV) -- the same virus that causes warts on other areas of the body. Some people are more susceptible than others to HPV, and not everyone will develop plantar warts if they come into contact with the virus. Individuals with weak immune systems or damaged skin on the feet are at a higher risk for plantar warts. br br Plantar warts most often develop on the weight-bearing areas of the foot -- the heel or the ball of the foot -- causing sharp, burning pain. They can appear as a single wart (solitary) or a cluster of warts (mosaic).