Corns and calluses

   Corns and calluses are thickenings of the outer layer of skin caused by friction, chronic irritation, or pressure. Corns are cone-shaped and have hard, shiny surfaces. The point of the cone extends deep into the skin and, upon pressure, pushes against the tender lower layers of the skin, causing pain. Corns can be cut away, although there is a danger of infection if the removal is not properly done. Before removal, corns are usually softened by ointments or medicated plasters. A common cause of corns is wearing shoes that do not fit properly.
   Calluses involve only the upper layer of skin and are generally not painful. They disappear without treatment when the cause of their formation is removed.