Hard bumps on the palms of the hands may be related to calluses, common warts, corns and scars. 1. Callus is a kind of skin keratinization formed due to long time friction and pressure on the skin, which is also called “callus”. 2. common warts is due to the infection of human papilloma virus and lead to a kind of skin disease, the main manifestation of a slightly prominent in the skin surface of the pimples, hard texture and surface roughness. 3. Corns are a kind of inverted cone-shaped keratosis formed by excessive friction and extrusion of the skin, and the center of the area can be painful and uncomfortable when pressed. 4. Scars are abnormal growths formed as a result of localized tissue damage. Hard bumps on the palm of the hand may have other causes, due to the complexity of the cause, the specific circumstances need to ask the doctor for an interview and then a clear diagnosis. Do not treat them blindly on your own.