Callus, also known as callus, can be divided into hand callus and foot callus, the reason for the formation of repeated friction with the skin and other conditions related. 1. Hand callus: for example, playing a musical instrument for a long time will lead to hardening of the skin in the fingertip area and the formation of callus. If you do manual work for a long time, contact with iron and other things, the palm of the hand and such items repeatedly friction, callus will also be formed. 2. Callus on feet: commonly seen in patients who wear ill-fitting shoes for a long time, due to the long-term extrusion of shoes or repeated friction, resulting in excessive friction of the skin on both sides of the feet, thickening callus. In addition, if the patient has bunion, walking posture abnormalities, etc., may form callus. It is recommended that patients with callus should consult the doctor in time, and if necessary, follow the doctor’s instructions for appropriate treatment.