A foot corn refers to the infection caused due to thickening of the skin on the top side of the toes from shoe pressure. In order to protect itself, the skin on the foot area thickens up and eventually becomes painful at the area of the corn. If coupled with inflammation or swelling around the corn, it can cause great deal of pain. Foot corns could appear in colors like yellow, white, brown and ray as per the type of skin. Main causes of foot corns include wearing tight fitting shoes, any stitch inside the shoe, abnormal walking, bunions, and at times, not wearing sandals with socks.