Perianal itching at night while sleeping and not during the day may be due to intestinal parasitic infections or due to the occurrence of perianal eczema, hemorrhoids, and other diseases. Medication and surgery are available. 1. Intestinal parasites infection: when patients with intestinal pinworm infection, adult worms will crawl out of the anus at night to lay eggs, stimulate the local mucous membrane and skin of the perianal area to form itching, accompanied by varying degrees of abdominal pain. 2. Perianal eczema: due to the patient suffers from hemorrhoids or sinusitis, in the night secretion will increase, and triggered by the local itching of the anus or perianal eczema-like changes, the daytime symptoms will be reduced or no symptoms. 3. Hemorrhoids: long-term incorrect defecation habits, irregular diet, often eat some spicy and irritating food induced hemorrhoids, will stimulate the perianal area, may cause a special itchy perianal area at night, accompanied by meatballs out, blood in the stool, defecation and other symptoms. If the patient appears to sleep at night perianal area itching, daytime does not itch the situation, should promptly go to the hospital to identify the cause, treatment.