Pruritus is a relatively common skin disease, the onset of which may be caused by dry skin, external stimuli, other diseases and other reasons. 1. Dry skin: dry skin is one of the common causes of pruritus, when the patient is in too dry environment, or due to skin aging, sebum secretion can be caused by dry skin, triggered by pruritus, in addition, the patient frequent bathing, the use of alkaline soap may also cause such cases. 2. External stimuli: when the patient contact pollen, dust, alkaline materials, synthetic woolen fabrics and other items, or the outside world, sudden and abrupt changes in temperature caused by skin irritation, may induce pruritus. 3. Disease: other diseases of the body is also one of the causes of pruritus, when the patient suffers from kidney disease, uremia, thyroid dysfunction, diabetes mellitus, desiccation syndrome and other malignant tumors and other diseases, can also cause generalized itching. It is recommended that patients seek medical examination in a timely manner to clarify the cause of the targeted treatment, pay attention to skin protection in life, avoid contact with irritating substances.