Dry skin and dry hair may be due to physiological reasons such as aging, or pathological reasons such as malnutrition and anemia. 1. Physiological reasons Ageing: Dry skin and dry hair can be caused by ageing. Ageing can lead to atrophy of sebaceous glands, which makes the sebaceous glands’ secretion function worse and causes dry skin and dry hair. 2. Pathological causes (1) Malnutrition: dry skin and dry hair may be caused by malnutrition, due to insufficient intake of nutrients or imbalance in the proportion of nutrients and other reasons leading to malnutrition, so that the body can not provide basic nutrients for the skin and hair in a timely manner, and for a long time can lead to dry skin and dry hair. (2) Anemia: dry skin and dry hair may also be caused by anemia, there is a decrease in the production of red blood cells or destruction of excessive, resulting in anemia, nutrients can not be transported to the skin and hair through the blood circulation, resulting in dry skin and dry hair. Dry skin and dry hair to exclude physiological causes, if the symptoms do not get better, it is recommended to go to the hospital in a timely manner, under the guidance of the doctor to carry out active treatment, do not blindly use their own medication to avoid adverse consequences.