Lower abdominal pain with anal swelling can be considered as three possibilities: first, acute proctitis, mostly caused by proctitis-causing bacteria infecting the rectal mucosa, with clinical manifestations of lower abdominal distension and pain, accompanied by urgency and anal swelling. Second, pelvic abscess, mainly acute purulent infection of pelvic tissues, pus stimulation of the rectal wall can appear anal swelling, accompanied by pain and discomfort in the lower abdomen. Third, perianal abscess, when the abscess spreads widely, it can cause lower abdominal distension and severe anal pain, usually accompanied by a feeling of anal swelling and incomplete defecation. Fourth, thrombosed external hemorrhoids, when the hemorrhoid is embedded and cannot be returned, due to the stagnation of blood in the hemorrhoid veins, it is easy to form thrombosed external hemorrhoids, which can cause anal swelling and severe anal pain, and can appear lower abdominal radiating pain. Therefore, when there is pain in the lower abdomen with anal swelling, you should visit a regular hospital’s anorectal surgery department to clarify the cause of the pain and carry out reasonable treatment under the guidance of a specialist.