The incidence of forefoot pain and deformity increases with age. With early diagnosis, conservative therapy is often successful in treating common disorders of the forefoot. The skin on the sole of the foot is ordinarily about forty times thicker than skin anywhere else on the body, but a callus can double this normal thickness. A protective callus layer naturally develops to guard against excessive pressure and chafing as people get older and the padding of fat on the bottom of the foot thins out. If calluses get too big or too hard, however, they may pull and tear the underlying skin.
Calluses can develop from wearing poorly fitting shoes and walking on hard surfaces.
People with flat feet are at an increased risk of developing calluses. In people with diabetes, particularly those who have had foot ulcers, the presence of calluses is a strong predictor of subsequent ulceration. Neuromas occur when the tissue surrounding a nerve becomes enlarged and inflamed causing a burning or tingling sensation and cramping. Morton's neuroma is the most common neuroma in the foot and usually develops when tight, poorly fitting shoes, often those with high-heels, cause the third and fourth metatarsal bones to pinch together compressing an underlying nerve. Injury, arthritis, or abnormal bone structures may also cause this condition.