Anal Fistulas: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Anal Fistulas?
A colorectal surgeon (a doctor who treats problems of the colon and rectum) usually treats anal fistulas. A gastroenterologist (a bowel doctor) may help when Crohn disease is the cause. Most fistulas need a procedure to heal. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What are anal fistulas?
An anal fistula is a small tunnel that connects the inside of the anus to the skin around it. The anus is the opening where stool leaves the body. A fistula is an abnormal connection between two body parts. Most anal fistulas start from an infected gland inside the anus. The infection builds up pus and forms a pocket called an abscess. When the abscess drains, the draining path can stay open as a fistula. Anal fistulas cause pain, swelling, and drainage of pus.
Symptoms
Symptoms often include:
- Pain and swelling near the anus.
- Drainage of pus from an opening in the skin near the anus.
- Skin irritation and itching around the opening.
- Pain that is worse when sitting or passing stool.
If an abscess forms, the area can become a swollen, red lump with throbbing pain and fever. These symptoms are often long-lasting and can keep coming back.
Causes and who gets it
Most anal fistulas come from an infection of small glands inside the anus. Doctors call this a cryptoglandular infection. Other causes include Crohn disease, trauma or surgery in the anal area, radiation to the pelvis, and some infections. Crohn disease often causes complex fistulas with more than one tract and a higher chance of coming back. Fistulas from anal cancer or radiation are also well documented.
How doctors diagnose it
A doctor examines the skin around the anus and does a rectal exam to find the internal opening. The exam shows where the external openings are and how the tract runs. For complex fistulas, MRI or endoscopic ultrasound can show the tunnel in detail. These tests show the fistula anatomy and how it relates to the sphincter muscle, which is the muscle that controls stool. Endoscopic ultrasound is another option that uses sound waves. If Crohn disease or cancer is suspected, doctors may do a colonoscopy, which is a camera exam of the inside of the colon.
Treatment
Treatment of anal fistulas is almost always surgical. For simple fistulas, the standard procedure is fistulotomy. The surgeon opens the tract so the wound heals from within. Because cutting muscle can affect control of stool, complex fistulas need other options. A seton is placed through the tract to keep it draining while the area heals. The LIFT procedure ties off (ligates) the tract and is a sphincter-saving option. An advancement flap is another option. Fibrin glue and fistula plugs seal the tract, but they fail more often. For fistulas from Crohn disease, biologic medicines are the main medical treatment. Warm sitz baths help with pain after surgery. After surgery, good hygiene and healthy bowel habits are important.
Surgery risks include bleeding, infection, stool leakage, and the fistula coming back. Doctors weigh these risks when choosing the procedure.
When to see a doctor
Call 911 or go to the emergency room if you have bleeding that will not stop, fainting, confusion, or sudden, severe pain. Get care right away if you have a painful, swollen lump near the anus with fever. Rectal bleeding, changed bowel habits, mucus in the stool, or weight loss are not common with a simple fistula. They need prompt checks to rule out other diseases. See a doctor for any lasting drainage or pain near the anus.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. This doctor can examine the area first and help keep the wound clean as it heals. They can also coordinate your care with a colorectal surgeon.
Common questions
Do anal fistulas heal on their own?
Usually not. Treatment is almost always surgical. A fistula that is still not healed after 12 weeks is considered a treatment failure and needs a different plan.
Will surgery affect my control of stool?
It can. Cutting the sphincter muscle can cause leakage. That is why doctors choose sphincter-saving options for complex fistulas. Fistulas that come back may need another procedure.
Can anal fistulas come back?
Yes. For simple fistulas, healing rates approach 80%. Fistulas come back more often when the cause is Crohn disease or when the internal opening is not found.
What is a seton?
A seton is placed through the fistula tract. It keeps the tract draining and helps it heal in stages. Doctors may tug it gently at regular intervals as the wound heals.
Sources
- NIH NCBI Bookshelf - Anorectal Fistula (StatPearls)
- MedlinePlus - Fistula
- MedlinePlus - Anorectal abscess
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
