Corns and plantar warts are common growths on the feet that often cause confusion due to their similar appearance and the discomfort they cause. While both are localized skin thickenings, their origins, physical characteristics, and treatment protocols are fundamentally different. Proper identification is necessary because the intervention for a corn (a mechanical problem) will not resolve a plantar wart (a viral infection).
The Underlying Causes: Friction Versus Virus
The most significant difference between a corn and a plantar wart lies in their distinct causes. A corn is a type of localized hyperkeratosis, which is the body’s protective response to repeated mechanical stress, pressure, or friction. This mechanical stress, often from ill-fitting footwear or a structural foot issue, causes the skin to thicken and form a dense, inverted core of hardened tissue.
Plantar warts are caused by an infection from the Human Papillomavirus (HPV), specifically certain non-sexually transmitted strains like types 1, 2, 4, 27, and 57. The virus enters the skin through tiny cuts or abrasions on the foot’s sole, leading to the formation of a lesion. Because a wart is a viral infection, it is contagious, unlike a corn, which is simply a buildup of skin cells reacting to pressure. The time from exposure to the virus until a wart becomes visible can range from two to six months.
Visual and Sensory Differences
The most practical way to distinguish between the two is by examining the lesion’s appearance and how it responds to pressure. A corn typically presents as a small, raised, hard bump with a translucent or yellowish center, often forming over bony prominences where friction is highest, such as on the tops or sides of the toes. Pain from a corn is usually elicited by direct, downward pressure, such as when standing or walking, because the dense core pushes into the underlying nerve endings.
Plantar warts, while often flattened by the pressure of walking, tend to have a rougher, grainier surface texture that disrupts the natural lines of the skin (dermatoglyphics). A distinct feature is the presence of tiny, dark spots, sometimes referred to as “seeds,” which are actually clotted capillaries that supply the wart with blood. Unlike a corn, a plantar wart often causes pain when squeezed from the sides, a diagnostic technique known as lateral compression. Warts can appear anywhere on the sole of the foot, and they may sometimes develop in clusters called mosaic warts.
Addressing and Treating Each Condition
Since a corn results from mechanical stress, treatment focuses on relieving the underlying pressure and friction. Simple measures like wearing properly fitted shoes, using specialized padding, or correcting structural foot issues are the initial steps to allow the corn to resolve.
For existing corns, management often involves mechanically reducing the thickened skin, which can be done with a pumice stone after soaking or through professional debridement using a sterile scalpel. If the source of pressure is not removed, the corn will continue to reform.
Plantar warts require a treatment approach aimed at destroying the infected skin cells or stimulating the body’s immune system to clear the virus. Common over-the-counter treatments for warts contain salicylic acid, which works by slowly peeling away layers of the infected skin.
Professional medical interventions include cryotherapy, which uses liquid nitrogen to freeze and destroy the wart tissue, or prescription topical medications. Because warts are contagious, care should be taken during self-treatment to avoid spreading the virus. It is advisable to seek medical attention if a lesion is excessively painful, if self-treatment is unsuccessful, or if a person has underlying conditions like diabetes or a compromised immune system.