Corns like calluses develop from an accumulation of dead skin cells on the foot, forming thick, hardened areas. They contain a cone-shaped core with a point that can press on a nerve below, causing pain. Corns are a very common ailment that usually form on the tops, sides and tips of the toes. Corns can become inflamed due to constant friction and pressure from footwear. Corns that form between the toes are sometimes referred to as soft corns.
Some calluses have a deep seated core known as a nucleation. This particular type of callus can be especially painful to pressure. This condition is often referred to as Intractable Plantar Keratosis.