1.Anal fissure. If there is a burst of pain in the anal area during and after defecation, with or without blood in the stool, and the stool is either dry or not dry. On anal examination, a poke-shaped fissure in the skin of the anal canal is visible. Anal fissure should be considered first. 2, thrombosed external hemorrhoid If suddenly found in the anal department, there is a swelling protruding, pain is obvious, it is always painful, oval or round, and painful to finger touch. Anal Jane, the swelling is dark or bruised. Thrombosed external hemorrhoids should be considered. 3.Perianal abscess. If the swelling and pain around the anus, it can be accompanied by fever, fidgeting, all the time pain, and perianal skin fever. On anal examination, the perianal skin is red, diffuse and swollen with unclear borders. Perianal abscess should be considered. 4.Mixed hemorrhoid impaction. The patient has a history of hemorrhoids, with the swelling prolapsing during stool, repeatedly prolapsing, suddenly not returning, suffocating at the anus, and gradually developing anal pain. It is hard to bear. Sitting and lying down. On anal examination, the internal hemorrhoid is seen to be ectopic and the mucous membrane has necrotic erosion, etc. 5.Malignant tumor in the anus. Such as anal canal cancer, malignant melanoma, etc.