Itchy skin without any symptoms may be caused by physiological factors such as dry weather, or it may be caused by old age pruritus, cholestasis, diabetes and other diseases. 1. Physiological factors: If the weather is too dry, it may lead to a faster loss of water in the body, resulting in dehydration of the skin, which may lead to itchy skin. 2. Pruritus in old age: the elderly due to the function of the cortical glands decreases, skin atrophy, dry, coupled with hot water excessive washing, easy to trigger itching of the skin, known as pruritis in old age. 3. Cholestasis: In patients with liver disease and cholestasis, itching is a common clinical manifestation. The exact substance that causes itching is not known, and it is thought to be caused by bile acids in the blood or skin. 4. Diabetes mellitus: Diabetes mellitus can also cause itching of the skin, which can be generalized throughout the body and more often limited to the perianal and genital areas. It may be caused by neuropathy, Candida infection, and dry skin. Causes of itchy skin without any symptoms of more reasons, in the exclusion of physiological factors, it is recommended to go to the regular hospital to clarify the cause of the disease.