An anorectal abscess is a localized collection of pus in the perirectal spaces. Abscesses usually originate in an anal crypt. Symptoms are pain and swelling. Diagnosis is primarily by examination and CT or pelvic MRI for deeper abscesses.
Treatment is surgical drainage. Anorectal abscesses may be superficial or deep. Superficial abscesses may be diagnosed clinically and drained in the office or emergency department. Deep abscesses often require imaging with CT scan and typically must be drained in the operating room. Immunocompromised patients and those with extensive cellulitis should receive antibiotics. Anorectal fistulas may develop after drainage.