While both corns and plantar warts have a similar appearance and feeling, they can be differentiated by certain characteristics. Plantar warts tend to be small, skin-colored, and rough to the touch, and also look grainy, with small black dots sprinkled around it or within it. They can also appear flat from pressure, depending on which area of the foot is affected. Corns lack a grainy appearance, but instead look like a hard raised bump with dry, flaky skin surrounding it. These variations are due to the different root causes of warts and corns: plantar warts are caused by the human papillomavirus (HPV), whereas corns are caused by excess pressure and friction, similar to how calluses are formed.