Anorectal abscess

Alternative names
Anal abscess; Rectal abscess; Abscess - anorectal

Definition
An anorectal abscess is a collection of pus in the anal or rectal region.

Causes, incidence, and risk factors

Infection of an anal fissure (cleft or slit), sexually transmitted infections, and blocked anal glands are common causes of anorectal abscesses. Abscesses may occur in an area that is easily accessible for drainage, or higher in the rectum. Deep rectal abscesses may be caused by intestinal disorders such as Crohn’s Disease or diverticulitis.

High-risk groups include diabetics, immunocompromised patients, people who engage in receptive anal sex, and patients with inflammatory bowel disease.

Superficial perianal abscesses are not uncommon in infants and toddlers who are still in diapers and have a history of anal fissures. The abscess often appears as a swollen, red, tender lump at the edge of the anus. The infant may be fussy from discomfort, but there are generally no other associated symptoms. Surgical drainage and antibiotics provide prompt relief in such cases.

Symptoms

     
  • Painful, hardened tissue in the perianal area  
  • Discharge of pus from the rectum  
  • Lump or nodule, swollen, red, tender at edge of anus  
  • Fever  
  • Pain associated with bowel movements  
  • Constipation (may occur)

Signs and tests

     
  • A rectal examination may confirm the presence of an anorectal abscess.  
  • A proctosigmoidoscopy may be performed to exclude associated diseases.

Treatment

Treatment involves prompt drainage of the abscess. Depending on the location of the abscess, the procedure may take place in an outpatient setting. If the abscess is very deep, surgery with appropriate anesthesia may be indicated.

Warm sitz baths (sitting in a tub of warm water) are useful for relief of pain and swelling, and may assist with localization of the abscess to permit drainage.

Pain medication and antibiotics may be needed.

Expectations (prognosis)

The probable outcome is good if the abscess is treated promptly. Infants and toddlers usually recover very quickly.

Complications

     
  • Systemic infection  
  • Anal fistula formation  
  • Recurrence  
  • Scarring

Calling your health care provider

Call your health care provider if rectal discharge or other symptoms of anorectal abscess develop.

Call your provider if fever, chills, or other new symptoms develop after treatment of an anorectal abscess.

Prevention

In adults and adolescents, prompt treatment or prevention of sexually transmitted diseases may prevent this cause of anorectal abscesses. Use condoms for anal intercourse to prevent such infections.

Frequent diaper changes and attention to hygiene and cleansing at diaper changes will help prevent both anal fissures and perianal abscesses in infants and toddlers.

Johns Hopkins patient information

Last revised: December 6, 2012
by Dave R. Roger, M.D.

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