Redness and pain in the anus, it has a particularly wide range of causes. If there is a history of such trauma, it can lead to redness, swelling, heat and pain around the anus. If there are no particularly obvious symptoms, conservative treatment can be carried out, and the condition should be closely observed. If an abscess forms around the area, a perianal ultrasound should be performed in a timely manner. The second one is the formation of perianal abscess due to the infection of the anal gland and its spread around the anorectum, which may also lead to redness and pain in the anus. The third possibility is anal fissure, which is a fracture of the skin around the anus caused by dry stool. If the fissure is stimulated by stool or strenuous exercise, the original fissure will further increase in size, and if combined with infection, it will also lead to perianal swelling and pain.