There are many reasons why the anus itches every night: 1, and physical condition, some people’s skin is prone to allergies, contact with chemical fiber clothing, toiletries, drugs and other substances will cause local itching of the skin. 2, anal infections, fungal infections, such as foot fungus disease patients wash feet and sitz bathtubs mixed, caused by fungal infections of the anus itching, itching in the evening at 8-9 o’clock will be aggravated. 3, anal dermatitis, eczema, is the cause of the itching around the anus and rectum. Itching around the anus and rectum is the cause of itching. 4, pinworms are rare, long time anal itching, especially at night, considering the pinworms caused by pinworms, pinworms crawling out at night around the anus will lead to serious itching at night in the anus department, with the improvement of the health condition, health consciousness, pinworms are very rare, poor areas, grass-roots level area still exists. To summarize, anal itching at night is due to physical causes, infections and pathological causes.