Hammertoe is the general term used to describe an abnormal contraction or “buckling” of the toe because of partial or complete dislocation of one of the toe joints.
As the toe becomes deformed, it rubs against the shoe, and the irritation causes the body to build up thicker skin to help protect the area. The common name for the thicker skin is a corn. At first, this thick skin helps reduce irritation to the bone prominence, but as the skin becomes thicker, it adds to the pressure from the shoe. Periodic trimming of the corn may give temporary relief. However, a bursa may develop over time, and if it becomes inflamed (bursitis), the area becomes red, swollen and painful and may also become infected.
Do not confuse corns with calluses that occur on the bottom of the feet. They are generally caused by other conditions, although a severe hammertoe may create downward pressure on a metatarsal bone at the ball of the foot and add to the cause of a callus.