Differential Diagnosis for Rectal Pus
- Single most likely diagnosis
- Anal abscess: This is the most common cause of rectal pus, typically resulting from an infection of the anal glands. The presence of pus usually indicates a need for drainage.
- Other Likely diagnoses
- Proctitis: Inflammation of the rectum can cause discharge, including pus, and can be due to infectious (bacterial, viral, or parasitic) or non-infectious causes (inflammatory bowel disease).
- Rectal fistula: An abnormal connection between the rectum and the skin can lead to the discharge of pus from the rectum.
- Diverticulitis: Inflammation of a diverticulum in the colon can lead to pus in the rectum, especially if the diverticulum ruptures.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Necrotizing fasciitis: A severe infection of the skin and soft tissues that can spread rapidly and is life-threatening if not promptly treated.
- Perforated viscus: A hole in the wall of the intestine can lead to leakage of intestinal contents, including bacteria, into the abdominal cavity, causing severe infection.
- Ischiorectal fossa abscess: Although less common, an abscess in this area can be life-threatening due to its potential to spread infection.
- Rare diagnoses
- Actinomycosis: A rare bacterial infection that can cause abscesses and fistulas in the rectal area.
- Lymphogranuloma venereum (LGV): A sexually transmitted infection that can cause rectal symptoms, including pus, in its late stages.
- Crohn's disease: A type of inflammatory bowel disease that can cause complications such as fistulas and abscesses, leading to rectal pus.