Corns usually form on the tops and sides of feet or between toes, according to WebMD. They appear as small, thickened patches of skin with central cores, and depending on the type of corn, the skin may feel hard or tender.
Corns occur at areas of frequent pressure, and they commonly develop a round or conical shape, states MedicineNet. Compared to the surrounding skin, a corn often appears flaky, dry, waxy or translucent, and it may cause pain exacerbated by walking and other foot motions. Common locations include the ball of the foot and the outer edge of the fifth toe. The previously described hard corns are the most common type. Soft corns usually have whiter coloring and a less uniform shape, and they are most likely to form between the fourth and fifth toes.
Seed corns are a smaller variant that typically form near weight-bearing areas, such as the bottom of the foot, explains WebMD. As of 2015, doctors believe they are triggered by blocked sweat ducts. In contrast, hard and soft corns are linked to foot problems that put prolonged or repetitive stress and friction on the skin, such as wearing poor-fitting footwear or shoes without socks. Women are four times more likely to develop corns, especially when they frequently wear high heels. In some cases, corns are caused by underlying foot deformities.