Itchy anus, go to the toilet to take a shit can not come out of the possible causes are anal fissure, perianal eczema, hemorrhoids and so on. 1. Anal fissure: anal fissure is due to dry or coarse stools lead to rupture or tearing of the skin of the anal canal, and in the skin breaks easily infected with inflammation, resulting in anal itching, pain, due to the pain caused by the fear of defecation and constipation. 2. Perianal eczema: perianal eczema is a kind of inflammatory reaction of the perianal skin, and then there is perianal moisture, poorly cleaned stool on the anal skin stimulation enhancement, resulting in anal itching, but also to go to the toilet to poop out of the situation. 3. hemorrhoids: hemorrhoids is a benign lesion in the anus, easy to bleed during defecation, pain, anal itching, hemorrhoids, prolapse symptoms, anal pain easily induced to go to the toilet to poop out. Anal itching, go to the toilet poop can not come out of the patient should be timely to the hospital, improve the condition under the guidance of the doctor treatment.