The causes of hardened and rough hand joint skin include skin keratinization, hand eczema and rheumatoid arthritis. 1. Skin keratinization: most of them are caused by skin keratinization, generally and long-term hand labor, wind and sun, resulting in joint skin wear, appear hard and rough, belongs to the normal physiological situation, in order to protect the fingers and the formation of callus. 2. Hand eczema: may be suffering from chronic eczema of the hands, often accompanied by dry hands, finger joints skin hypertrophy and roughness, often cracked in winter, most common in housewives, so also known as the “housewife hand. 3. Rheumatoid arthritis: rheumatoid arthritis can lead to deformation of the joints of the hands, pain, stiffness, etc., but also cause the joints of the skin hardness, roughness and other skin changes. The skin of the joints of the hands becomes rough and hard can also be caused by other reasons (such as ringworm), it is recommended to consult a doctor as soon as possible to find out the cause, if it is caused by pathological reasons, it should be actively treated under the guidance of a physician.