A painful lump on the sole of the foot often leads to the same question: Is this a corn or a plantar wart? These two common foot lesions can appear similar, yet they have entirely different origins and require distinct treatment approaches. One is a contagious infection, while the other is a non-contagious response to mechanical stress. Understanding the distinctions between a plantar wart and a corn is the first step toward effective treatment.
Understanding Plantar Warts
Plantar warts are growths on the sole of the foot caused by an infection with the Human Papillomavirus (HPV). The virus invades the outer layer of skin, usually entering through tiny cuts or breaks. Because the virus is contagious, warts can spread, often thriving in warm, moist environments like public showers or locker rooms.
Due to the constant pressure of walking, plantar warts tend to grow inward, making them painful, especially when standing or walking. The surface of a wart is typically rough and grainy, and its presence disrupts the normal, parallel lines of the skin. A distinguishing feature is the presence of small, dark pinpoints, often called “wart seeds,” which are actually tiny clotted blood vessels pushed to the surface.
Understanding Corns
Corns, unlike warts, are not caused by a virus but are a form of hyperkeratosis, or localized thickening of the skin. This buildup of hardened, dead skin cells is the body’s protective response to repeated friction or excessive pressure on bony areas. The most common causes are ill-fitting shoes or structural foot issues that cause uneven pressure distribution.
Corns are typically small, round, and hard, often presenting with a dense, translucent central core that points inward. Hard corns usually form on the tops and sides of the toes. Soft corns, which are kept moist by sweat, develop between the toes. Since corns are mechanical in origin, they are not contagious and do not feature the dark blood vessels seen in viral warts.
Key Differences Between Warts and Corns
The differences in pain profile offer one of the most reliable ways to distinguish between the two. A corn usually hurts most when direct, inward pressure is applied, as the hard core presses against underlying nerve endings. Conversely, a plantar wart tends to be more painful when the lesion is squeezed from side to side.
Visual cues also provide clear diagnostic indicators. When the lesion is pared down, a corn will appear yellowish or translucent and maintain the normal parallel skin lines. In contrast, a wart has a rougher, more granular texture, and its growth pattern visibly interrupts the natural ridges of the skin. The hallmark sign of tiny black or brown dots, representing dried blood, is unique to the viral wart and is absent in a corn.
The location of the growth often provides another clue. Corns almost exclusively form directly over points of mechanical pressure or friction, such as a knuckle of a toe. While plantar warts can occur on weight-bearing areas, they can also form in non-pressure areas. Warts often appear in clusters known as mosaic warts, a pattern not seen with corns.
Treatment Approaches
Treatment for a plantar wart focuses on destroying the virus-infected tissue. Over-the-counter and prescription-strength topical solutions containing salicylic acid work by chemically peeling away the layers. For more persistent warts, professional treatments include cryotherapy, which involves freezing the tissue with liquid nitrogen, or minor surgical procedures to excise the growth.
Managing a corn centers on relieving the mechanical pressure and friction that caused the hyperkeratosis. This may involve wearing properly fitted shoes, using protective padding, or placing orthotics to redistribute pressure. A healthcare professional, such as a podiatrist, can safely trim or shave the hardened skin away, providing immediate pain relief. If the lesion is painful, bleeding, or if you have underlying conditions like diabetes, consulting a podiatrist or dermatologist is highly recommended for accurate diagnosis.