Today a bunionette is most likely caused by an abnormal bump over the end of the fifth metatarsal (the metatarsal head ) rubbing on shoes that are too narrow. Some people's feet widen as they grow older, until the foot splays. This can cause a bunion on one side of the foot and a bunionette on the other if they continue to wear shoes that are too narrow. The constant pressure produces a callus and a thickening of the tissues over the bump, leading to a painful knob on the outside of the foot. Hallux valgus is a chronic, but often painless structural abnormality of the foot that involves permanent inflexibility of the bones. This type of bunion strains the foot, creates an abnormal bulge at the affected toe joint, widens base of the foot and interferes with standing and walking, according to USA Today. People who have hallux valgus are at risk of developing early arthritis due to the loss of bone and power in the foot. This type of growth usually occurs when a faulty foot structure or ill-fitting shoes causes a misalignment of the toes. References. A common cause of calluses on the bottom of the foot is shoes that fit poorly. Tight shoes and high heels compress different parts of the foot, and loose shoes can cause your foot to rub repeatedly against the sole. Not wearing socks also can lead to calluses. Another common cause is an abnormality in your gait that causes you to carry weight in certain areas of your foot more than you carry it in others, according to the website ePodiatry. Having bunions on your feet also can cause calluses as the bunions rub against your shoes. Symptoms A complaint which is more common among men then women is "Hallux rigidus", where, instead of bending normally, the big toe stiffens and forms a bump at the top of the joint, making the 'pushing-off' motion in walking difficult. This often results from stubbing or injury to the toe, perhaps during sport. Women often suffer from "Hallux rigidus" as a result of persistent trauma to the joints from slip-on or shoes that are too tight. Use appropriate moisture to keep your feet hydrated, and always wear right fitting footwear. Too tight or too loose a shoe can lead to foot problems like bunions , corns and fungal infections. I can find little to agree with Mark Davies. Neither corns nor callouses are “the result of a bone prominence rubbing against another bone”. Corns are a response of the skin to abrasion against footwear and calluses are a complex (but easily corrected) foot-floor interface problem. A “soft corn” is unusual, but does result from follow pressure between the toes, almost always when there is an “osteophyte” (a small arthritic prominence fron the joint) present. Scratching and rubbing can lead to further complications. Certainly, never try to "file down" hardened skin or calluses on your dry feet with a pumice stone since pumice is porous and can harbor harmful bacteria.