Itchy anal opening may be caused by perianal eczema, anal fissure, hemorrhoids and other diseases. 1. Perianal eczema: usually due to autonomic dysfunction, heredity and other factors, resulting in perianal skin perversion disease. Its clinical symptoms are often manifested as anal itching, dampness, fluid overflow and so on. 2. Anal fissure: usually due to infection, anal canal stenosis and other factors leading to the formation of anal skin fissure. If it is not treated in time, it may lead to fecal matter residue, which may lead to itchy anus. 3. Hemorrhoids: usually caused by a variety of factors such as poor bowel habits and improper diet. The anal skin folds more, hemorrhoid patients after defecation, not wipe clean, may appear in the anal opening itching phenomenon. Itchy anal opening may also be related to sinusitis and other diseases, it is recommended that patients seek timely medical examination, to avoid delaying the condition leading to adverse consequences.