Pain at the anal opening may be caused by perianal abscess, sinusitis, anal fissure and other reasons. 1. Perianal abscess: Perianal abscess is usually an acute suppurative infectious disease that occurs around the anus, anal canal and rectum, which may be caused by bacterial infection and surgical trauma, etc. Patients usually have anal pain, swelling, dysuria, poor digestion and defecation, poor appetite, insomnia and other symptoms. 2. Sinusitis: Sinusitis is an inflammatory lesion in the anal crypt of the dentate line of the anus, which is usually caused by improper diet and bacterial infection, etc. Patients may experience anal pain, foreign body sensation, increased secretion and other symptoms during defecation. 3. Anal fissure: anal fissure generally refers to the surface of the narrowest anal canal tissues of the human body cracked, the formation of small ulcers, may be due to the patient’s infection, constipation and other reasons for the patient, the patient will generally appear anal pain, blood in the stool and other symptoms. In addition to the above several diseases caused by anal pain, there will be thrombosed external hemorrhoids, internal hemorrhoids embedded and infections and other diseases can also cause anal pain, the causes are complex, the specific condition of the patient is recommended to go to the hospital in a timely manner, comprehensively identify the cause of the disease, differential diagnosis, in the guidance of the doctor to carry out a reasonable standardization of treatment.