Days and nights anal itching phenomenon, mostly due to perianal diseases and systemic lesions caused by the specific causes include the following: 1, parasitic infections caused by itching symptoms, especially pinworms are mostly pinworms, pinworms are a kind of intestinal parasites, especially at night, often climb out of the anus, in the anal periphery of the activities, thus causing the emergence of itchy symptoms. 2, hemorrhoids caused by the itching symptoms. . The appearance of hemorrhoids is mainly due to the occurrence of varicose veins around the anus caused by the formation of many thrombi or venous blood clusters around the anus, to the night by the stimulation of intestinal fluids, which will cause itching, or even painful symptoms. 3, anal fissure caused by itching symptoms. Anal fissure will form many small fissures in the skin around the anus, and when stimulated by feces and body fluids, itching and redness will occur. In addition to these reasons, allergic reactions caused by a variety of reasons, will also appear at night itching symptoms.