Corns or Intractable Porokeratoses are very painful lesions that can occur on the bottom of feet. Corns are essentially clogged sweat glands. They are skin lesions and can run in the family. They have a predilection to form on areas of the foot that weight bear but just as commonly form in areas that don't. Callouses are different in nature but can feel the same as a corn on the bottom of a foot. Callouses are more broad areas of thickened skin that form from shear due to walking. Usually callouses are accompanied by foot deformities such as bunions, hammertoes and flat feet.
Treatments for corns and callouses include trimming away excess skin with a scalpel, medicated patches such as Salicylic acid patches, orthotics with off loading areas. In some cases surgery involving correction of an underlying deformity to address a callous or simple excision of a corn may be necessary.
Its important to get these painful lesions examined by an expert as they can easily mimic warts, cysts or other dermatologic conditions that cause thickening of skin.