Fistula-in-Ano

Condition: Fistula-in-Ano (peri-anal abscess or sinus tract)

Overview (“What is it?”)

  • Definition: A fistula-in-ano (also known as perianal fistula) is an abnormal connection between the anal canal and the skin around the anus (Figure 1). A perianal abscess is a collection of pus or infection near the anus. These two conditions often occur with each other. 
  • Epidemiology: Fistula-in-ano occurs most commonly in infants younger than one year of age. A fistula-in ano is usually caused by an infection or abscess.

Signs and Symptoms (“What symptoms will my child have?”)

  • Early signs: The first sign of a perianal fistula is a perianal abscess which is a tender, red mass around the anus in an infant. 
  • Later signs/symptoms:  If left untreated, the abscess can get bigger and the baby can have fevers. Sometimes, the abscess can pop open and drain. If the abscess has an associated fistula, recurrent abscesses or a small draining opening at the same site can happen.  

Diagnosis (“What tests are done to find out what my child has?”)

  • A perianal abscess can be diagnosed by physical exam. To identify whether there is an associated fistula, sedation or anesthesia is needed.
  • Labs and tests:  No labs are typically necessary in infants with a fistula. In older children (above toddler age), a perianal abscess or fistula may signify an intestinal inflammatory process (inflammatory bowel disease). Further workup is needed in an older child.
  • Conditions that mimic this condition:  Perianal abscess without fistula; inflammatory bowel disease.

Treatment (“What will be done to make my child better?”)

  • Medicine:  Your child may be given medicine for pain and for any fevers (Acetaminophen [Tylenol®] or Ibuprofen [Motrin®]). You may also be given an antibiotic, which is a medicine to treat the infection. 
  • Surgery:  Drainage of the abscess may be all that is necessary for some children who present with a perianal abscess and no obvious fistula  If the abscess returns, alternatives include repeat drainage of abscess or a fistulotomy (unroofing of the sinus tract) may be performed (Figure 2). This is typically an outpatient procedure, and your child should be able to come home the same day.  
    • Preoperative preparation:  Your child will have to have an empty stomach for several hours prior to anesthesia. Intravenous (IV) antibiotics may be given just before surgery.
    • Postoperative care:  You will likely be instructed to begin bathing your child in warm, soapy water after each bowel movement to keep the wound clean. You may be asked to continue antibiotics and pain medications. For either drainage of abscess or unroofing of fistula, the wound needs to heal from the bottom up. It takes a few days (1-2 weeks) for the wound to completely heal over.
  • Risks/Benefits:
    • Risks of surgery include bleeding, infection and recurrence of the wound.
    • Risks of not treating the abscess or fistula is progression of infection which may spread to the surrounding skin or into the bloodstream.
    • Most often, drainage of abscess solves the problem. If the abscess recurs multiple times, then a fistulotomy would solve the issue.

Home Care (“What do I need to do once my child goes home?”)

  • Diet:  There are no dietary restrictions.
  • Activity:  There are no activity restrictions.
  • Wound care:  Bathe in warm, soapy water after each bowel movement until the wound is healed (typically 1-2 weeks).
  • Medicines:  Prescriptions for antibiotics and pain medications may be prescribed.
  • What to call the doctor for:  Call for persistent fevers, increasing pain or increasing redness around the wound.
  • Follow-up care:  You may follow up with your pediatrician or surgeon 1-2 weeks after fistulectomy to make sure the wound is healing appropriately.

Long-Term Outcomes (“Are there future conditions to worry about?”)

Once the fistula is removed, the chance of recurrent problems is very low. Recurrent abscesses or fistulas after adequate treatment will need further studies to determine the underlying cause.


Updated: 11/2016
Author: Patricia Lange, MD
Editor: Marjorie J. Arca, MD