The most common cause of eczema is asteatotic eczema. It is an eczema with clinical manifestations of dry, cracked, fine flaking skin followed by eczema due to the loss of moisture caused by the reduction or loss of the skin’s lipid film. Also known as winter itch, dry skin, dry eczema and chapped eczema. This disease is related to the reduction or malfunction of the skin surface oil: 1. congenital: congenital reduction of oil, seen in patients with ichthyosis or atopic dermatitis; 2. physiological: seen in people over 40 years old. Due to the natural decline of sebaceous gland and sweat gland function, dry skin occurs in winter. Generally around 30 to 40 years old, it starts to itch after bathing, and gradually worsens with age; 3, environmental factors: such as low air humidity in winter, dry environment due to heating, cold causes sebum and sweat secretion to decrease; 4, human factors: such as too many times of bathing, using strong alkaline soap, facial cleanser or bathing water temperature is too high, which can also cause artificial skin degreasing. The use of degreasing agents, such as alcohol is more likely to occur. Excessive washing or the use of degreasing preparations can cause a rapid onset of the disease, commonly on the hands and face. There have been seen due to fear of infectious diseases, excessive bathing caused by the whole body lack of lipid eczema; 5, disease: diseases such as malnutrition, various tumors, the use of diuretics, neurological diseases resulting in skin loss of nutrition, diabetes, hypothyroidism, radiation exposure, etc. can trigger this disease. You want to go to the hospital to check what kind of cause it is and treat it in a targeted manner.