Anal Fistual and Perianal Abscess

Anorectal disorders occur at the junction of the anal canal and the rectum. Often times treatment is available in an office setting, but occasionally require more complex treatments.

Learn what anal fistulas and perianal abscesses are, what the symptoms are your surgical options and more.

Anal fistula

An anal fistula is a tunnel that forms between an infected anal gland or anal abscess, and the skin on the outside of the body. This is a complication of an anal abscess. It usually starts as an anal abscess and will eventually create an abnormal tunnel out to the skin surface to allow the infection to drain itself. About 25-30% of people with an anal abscess will develop a chronic anal fistula; this can cause persistent drainage around the rectum, even after the abscess is treated.

Symptoms of an anal fistula

The symptoms of an anal fistula are the same as the symptoms of an anal abscess. But the pain is not as bad and may happen only during a bowel movement. Other symptoms can include:

  • Red, itchy skin near the anus
  • Pus or cloudy fluid draining from the anus

Testing for anal abscesses or fistulas

To check for an anal abscess or a fistula, your doctor or nurse will look at your anus and do a “digital rectal exam.” During a digital rectal exam, your doctor or nurse will put a gloved finger into your anus and rectum to feel for lumps or anything abnormal.

He or she might also order an “imaging test,” such as an MRI or a CT scan. Imaging tests create pictures of the inside of the body, which will help determine how severe or how large the abscess is.

Your doctor may also need to do other tests to check for sexually transmitted infections, inflammatory bowel disease, or rectal cancer.

Treatment for Anal Fistula

To treat a fistula, your doctor will need to cut open the abnormal tunnel that has formed; this will remove the pus and chronically inflamed tissue, and will help it heal. This is a surgery that is done under anesthesia with you asleep. If you have a large or deep fistula, you might need to be treated in a hospital.

Risks of surgery for anal fistula:

The main concern with surgery is the development of anal incontinence. If the anal fistula is deep, the doctor may need to cut through the anal sphincter to open the tunnel; if the anal sphincter is cut through entirely, it could result in anal incontinence. Anal incontinence can include inability to control gas, mild fecal soiling, or loss of solid stool. Some degree of leakage can occur in up to 45 percent of patients in the immediate surgical recovery period secondary to the surgical healing process and may be mistaken for incontinence by patients. However, this immediate post-surgical incontinence is rarely permanent and is usually mild.

**The risk of incontinence after surgery is higher in women who have had previous vaginal childbirth, or in any patients that has had previous anal or rectal surgery. The risk should be discussed with your surgeon.

After surgery

**It is very important to not allow yourself to become constipated after surgery.**

  • To avoid constipation or stool impaction, we recommend starting a high fiber diet the morning after surgery (Bran cereal, wheat or rye bread, fresh fruits, and vegetables) and also one tablespoon of Metamucil with 8 ounces of water each morning and evening starting the day after your surgery.
  • You should take Dulcolax stool softener (Docusate is the generic name) 100mg tablet twice daily starting on the day before your surgery, and until you are no longer taking pain medication.
  • If you go 48 hours without a bowel movement (BM), you should take 2 tablespoons of Milk of Magnesia every 6 hours until your first BM, and then stop.
  • Call the office if you go more than 2 days without a BM or if you are having abdominal pain or abdominal distension.
  • Drink plenty of water and juice and eat fresh fruits and vegetables.

Learn more about anal fistulas.

Anal Abscess

An anal abscess is a painful, inflamed soft mass filled with pus that forms alongside the anus This happens when an anal gland inside the anus becomes clogged and subsequently infected from the bacteria in the stool and anal canal. This can also be called a Perianal abscess (meaning around the anus) or Perirectal abscess (meaning around the rectum, just above the anus).

Symptoms of Anal Abscess

The symptoms of an anal abscess include:

  • Severe, constant pain or pressure in the anal area, often worse with bowel movements or sitting
  • Area of redness and warmth to the touch beside the anus, has a boil-like appearance
  • Fever or chills
  • Feeling ill

In some cases the abscess will open on its own and drain pus.

Causes of Anal Abscesses

An anal abscess can have many different causes including:

  • Infection of an anal fissure (a small tear in the skin of the anus)
  • Sexually transmitted infections
  • Blocked anal glands

Other risk factors for anal abscesses include:

  • Inflammatory bowel disease such as Crohn's or Ulcerative colitis
  • Other types of colitis or diverticulitis
  • Diabetes
  • Poor immune system, or use of medications that suppress the immune system (such as steroids or chemotherapy)
  • Having anal intercourse
  • Pelvic Inflammatory disease

Treatment for Anal Abscess

The abscess, if it has not opened on its own, needs to be surgically opened to allow the infection to drain out. Your doctor will cut a small hole in the skin over the abscess to drain out the pus. Often, this can be done in a doctor’s office. If you have a large or deep abscess, you might need to be treated in a hospital, with surgery under anesthesia.

After the abscess is opened and drained, you may have an open wound, which will allow the wound to heal; closing the skin over the infection will cause the infection to come back. Your doctor will give you specific instructions to take care of the wound after it is opened.

You will be instructed to:

  • ake “sitz” baths – This is a shallow, warm bath that helps clean and heal the anal area. Take them 3-4 a day (and after bowel movements) for 15-20 minutes each. You can buy a sitz bath tub over the counter at any pharmacy, or fill your bathtub with 2-3 inches of water.
  • Use a hand-held shower to gently spray the anal area to cleanse it at least daily. It is important to keep the area clean and dry as it heals.
  • Avoid creams or ointments on the anal area unless instructed otherwise.

*It is important that you follow up with a surgeon about 6-8 weeks after you have an abscess drained to evaluate if you have an anal fistula. If you have an anal fistula as well, this will need to be treated to prevent abscesses from occurring in the future.

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