Plantar warts are caused by a viral infection in the skin on the bottom of the foot. The virus enters through tiny breaks in the skin and triggers extra skin growth that forms the wart.
Main cause
Plantar warts are caused by certain strains of human papillomavirus (HPV), a common skin-infecting virus. These strains infect the outer layer of skin on the soles of the feet, especially in areas that bear weight like the heel or ball of the foot.
How the virus gets in
The virus usually enters through small cuts, scratches, or softened, damaged skin on the bottom of the foot. Once inside, HPV causes the outer skin cells to multiply, leading to a hard, rough growth that becomes the plantar wart.
Where infection happens
HPV that causes plantar warts thrives in warm, moist environments such as swimming pools, locker rooms, and communal showers. Walking barefoot on contaminated surfaces in these places increases the chance of picking up the virus.
Contagion and spread
Plantar warts are contagious and can spread through direct skin-to-skin contact or indirectly via shared items like towels, socks, or shoes. The virus can also spread on the same person if the wart is picked at or scratched, transferring the virus to nearby skin.
Risk factors
Plantar warts are more common in children and teenagers, people with weakened immune systems, and those who have had plantar warts before. Frequently walking barefoot in public wet areas or having small foot injuries also raises the risk of developing them.