Anal and Rectal Abscess

Definition
An anal abscess, also known as a rectal abscess, is an infected pustule located near the anus or rectum. Most anal abscesses are the result of glands within the anal canal becoming clogged, allowing bacteria or fecal matter to accumulate and infect the gland. This infection becomes a pus-filled cavity called an abscess. Patients with an anal or rectal abscess may eventually develop an anal fistula, which is an infected tunnel that forms between the anal canal and the skin near the anus.

Causes
Although there is no known cause for anal and rectal abscesses, the American Society of Colon and Rectal Surgeons reports 90% of abscesses are the result of an acute infection within an anal gland. Additionally, up to 50% of anal and rectal abscesses may recur despite proper treatment and healing.

Risk Factors
Patients with diabetes and inflammatory bowel disease generally have a greater risk of developing an anal and rectal abscess than patients who don’t have these health conditions. Additionally, those who engage in receptive anal sex appear to be at risk of developing a perianal abscess.  

Symptoms
The most common symptoms of an anal and rectal abscess include:

  • Redness, swelling, tenderness, or a mass around the anus
  • Anorectal pain
  • Fever
  • Rectal bleeding
  • Painful urination
  • Drainage from the perianal skin (anal fistula)

Treatments
Treatment for an anal and rectal abscess generally requires surgical drainage. This minimally invasive procedure is usually performed with a local anesthetic in a clinical setting (physician’s office). Anal or rectal abscesses prone to infection may require an operating room and deeper anesthesia for surgical drainage. Most anal and rectal abscesses that receive surgical drainage resolve and do not demand further treatment. However, recurring anal and rectal abscesses may indicate an anal fistula, which typically warrants a fistulotomy for treatment.