A corn on the foot looks like a small, round bump of thickened skin with a hard, dense center. It’s typically yellowish or grayish, surrounded by dry, flaky skin, and smaller than a dime. Unlike a callus, which spreads over a broader area, a corn has a well-defined border and a visible core, or nucleus, that points inward toward the bone beneath it.
Hard Corns
The most common type of corn is a hard corn, which forms on the tops or sides of toes and on the ball of the foot. It looks like a compact, raised dome of tough skin. The outer ring is typically dry and slightly yellowish, and in the center you can often see a translucent or darker plug of densely packed skin. That central core is what distinguishes a corn from ordinary thickened skin. It acts like a cone pressing inward, which is why even a small corn can cause sharp, focused pain when you press on it or put weight on your foot.
Hard corns range from about the size of a pencil eraser to slightly larger. The skin around them may look irritated or slightly reddened, especially if your shoes have been rubbing against the spot. Over time, the surface can become waxy or polished-looking from repeated friction.
Soft Corns
Soft corns look quite different. They form between the toes, most often in the narrow gap between the fourth and fifth toes, where bone presses against bone. Because this space traps moisture from sweat, the corn stays soft and rubbery rather than hardening. It appears whitish or grayish and has a slightly macerated, damp texture, almost like skin that’s been soaked in water too long. Soft corns can be harder to spot because they hide between the toes, but they’re often more painful than hard corns due to the sensitive skin in that area.
The underlying cause is the same as a hard corn: pressure from a bony prominence pushing against skin. But the moist environment changes the way the thickened skin develops, giving it that distinctive soggy appearance.
Seed Corns
Seed corns are the smallest variety. They look like tiny, discrete dots of hardened skin on the sole of the foot, often appearing in clusters. Each one is roughly the size of a pinhead or small seed. They tend to show up on non-weight-bearing parts of the sole and are generally painless or only mildly tender. Because they’re so small, people sometimes mistake them for dry skin or minor blemishes.
How a Corn Differs From a Callus
Corns and calluses both involve thickened skin, but they look and feel different. A callus is a broad, flat patch of toughened skin without a defined center. It spreads across a wider area, often covering the ball of the foot or the heel, and has blurry, gradual edges. A callus is rarely painful on its own.
A corn, by contrast, is compact and circular with a sharp border. The defining visual feature is that central core or plug. If you were to pare away the surface layer of a corn, you’d see a small, glassy cone of hard keratin pointing downward into the skin. Calluses don’t have this structure. If the thickened patch on your foot is small, round, and has a noticeable center, it’s almost certainly a corn rather than a callus.
Corn vs. Plantar Wart
This is the comparison that trips people up most, because both can appear on the bottom of the foot and both involve thickened skin. But the visual differences are reliable once you know what to look for.
A corn is hard, raised, and flaky with smooth skin lines running across it. The natural ridges of your skin (like fingerprints, but on your foot) continue through a corn without interruption. A plantar wart, on the other hand, disrupts those skin lines. It has a grainy, fleshy texture and, critically, tiny black pinpoints scattered across its surface. Those black dots are small, clotted blood vessels and are a hallmark of warts. Corns never have them.
If you squeeze the spot from the sides and it hurts, that points toward a wart. If direct downward pressure is what causes pain, it’s more likely a corn. Podiatrists use these same visual markers: normal skin lines suggest a corn, while disrupted skin lines and pinpoint bleeding when the surface is trimmed indicate a wart.
Why Corns Form Where They Do
Corns develop at specific pressure points. Tight or narrow shoes push the toes together and against the shoe’s interior, creating friction on the tops and sides of toes. High heels shift body weight forward onto the ball of the foot, which is why corns commonly form there. Bony foot structures like hammertoes or bunions create prominent spots that rub repeatedly against footwear.
The body responds to this repeated friction by building up layers of a tough protein called keratin, the same material in your fingernails. But instead of spreading out like a callus, the pressure gets focused on a small point, and the thickened skin forms a cone that presses inward. This inward-pointing structure is what makes corns painful: you’re essentially walking on a small plug that digs into the tissue beneath it with every step.
Signs of an Infected Corn
An uncomplicated corn is annoying but not dangerous. It becomes a concern when the skin breaks down or becomes infected. The visual warning signs are redness spreading beyond the corn itself, swelling in the surrounding skin, and any oozing or pus coming from the area. An infected corn may also feel warm to the touch and significantly more painful than before. People with diabetes or poor circulation in their feet need to take any skin breakdown on the foot seriously, since even a minor injury in that situation can develop into an open sore that’s slow to heal.