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Anorectal abscess



Anorectal abscess is defined as a localized collection of pus in the anorectal region, which is typically caused by an infection in the anal glands.
The pathophysiology of anorectal abscess usually involves an obstruction of the anal glands, which leads to bacterial overgrowth and subsequent infection. The infection can then spread to the surrounding tissues, causing an abscess to form.
The incidence of anorectal abscess in the United Kingdom is estimated at 20.2 per 100,000 person-years.
Disease course
Clinical manifestations of anorectal abscess include severe pain in the anorectal area, swelling, redness, and sometimes systemic signs of infection such as fever. In some cases, the abscess may rupture and drain spontaneously and complications can also occur, including the formation of a fistula.
Prognosis and risk of recurrence
The prognosis of anorectal abscess is generally good with early diagnosis and appropriate treatment, which typically involves surgical drainage of the abscess.


Key sources

The following summarized guidelines for the evaluation and management of anorectal abscess are prepared by our editorial team based on guidelines from the American Society of Colon and Rectal Surgeons (ASCRS 2022,2020), the American College of Radiology (ACR 2021), the World Society of Emergency Surgery (WSES/AAST 2021), the American College of Gastroenterology (ACG 2018), and the Association of Coloproctologists in ...
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Diagnostic investigations

Clinical examination: as per ASCRS 2022 guidelines, elicit a disease-specific history and perform a physical examination assessing symptoms, relevant history, location of the abscess and fistula, and the presence of secondary cellulitis in the initial evaluation of patients with anorectal abscess.
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  • Laboratory tests

  • Diagnostic imaging

Medical management

Antibiotic therapy: as per ASCRS 2022 guidelines, reserve antibiotics for patients with anorectal abscess complicated by cellulitis, systemic signs of infection, or underlying immunosuppression.

Surgical interventions

Incision and drainage: as per ASCRS 2022 guidelines, perform prompt incision and drainage in patients with acute anorectal abscess.

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  • Concomitant fistulotomy

Specific circumstances

Patients with Crohn's disease: as per AAST/WSES 2021 guidelines, perform adequate surgical drainage of a perianal abscess without searching for an associated fistula in patients with Crohn's disease.
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