How to Treat Anal Fistula(swollen anus) and What are Its Symptoms?

anal fistula treatment
Medically reviewed by Dr. Mandy Liedeman


Fistulas are abnormal tube-like connections between organs or vessels within the body.

An anal fistula that is also known as anal cyst, is filled with fluid that may be leaking.

The fistula discharge color of clear yellow, thin brown or tinged brown.

Anal fistula or perianal fistulas can form between anal canals and openings,vagina-rectum, and colon-vagina. Many medical conditions can be confused with fistula. 

To get the right information about the anal fistula, please read the article till the end.

What is Anal Fistula?

An anal fistula, or perianal fistula or Fistula-in-Ano, is a little tunnel inside the anus and the outer part of the opening around the anus. Anus is where the faeces exit the body, and it’s a muscular ending of the gastrointestinal tract.

There are many glands in your anus that produce fluid. If they get blocked, bacteria can be collected there, leading to infection, called an ‘perianal abscess.’

Perianal abscesses in female common sites are Hair follicles and sweat and oil glands of the vulvar skin.

If the abscess is left untreated, it grows and goes outside the body around your anus to drain the pus inside. A fistula develops under the skin; the path connects the drainage tract to the anal gland. 

Besides anal fistula, other common types are:

Urinary tract fistulas can form between:

  • The bladder and the uterus
  • The bladder and the vagina
  • The urethra and the vagina

Gastrointestinal fistulas can form between:

  • A pair of intestines
  • The gastrointestinal tract and the skin
  • Bladder and part of the intestine

In the gastrointestinal tract, aortoenteric fistulas may form between an aortic graft and a native aorta. In addition, they may form between a prosthetic aortic graft and any part of the intestine. Fistulas other than aortoenteric fistulas can usually be managed outpatient electively, but aortoenteric fistulas treatment in worse condition is surgical treatment.

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Types of Anal Fistula 

There are different types of anal fistulas depending on their location. Following is a list of the most common types in order of least common:

Inter sphincteric fistula 

Intersphincteric fistulas are abnormal ducts found near the anus or rectum. It is called an intersphincteric fistula-in-ano because it begins between the internal and external sphincters and ends in the anus. Intersphincteric fistulas have a high recurrence rate. Around 50% of patients undergoing treatment suffer from the same condition months after recovery.

Transsphincteric fistula

It begins in the space between the internal and external sphincters or behind the anus. After crossing, the external sphincter opens an inch or two outside of the anal opening. Two external openings outside the trans sphincteric fistula (horseshoe fistula) wrap around the body in a U-shape.

Suprasphincteric fistula

The tract starts in the space between the internal and external sphincters and extends upward and crosses the puborectal muscle, then extends downward between the puborectalis and levator ani muscles and opens outside the anus.

Extrasphincteric fistula

This tract extends downward from the rectum or sigmoid colon, passes through the levator ani muscle, and opens around the anus. The three most common causes of extra sphincteric fascias are appendiceal abscesses, diverticular abscesses, and Crohn’s disease.

Causes of Anal Fistula

Less common causes of Anal Fistula are:

Diverticulitis: it is an infection of little pockets (diverticula) that grows in the lining of the large intestines (colon)

Crohn’s Disease: It is a longtime condition where the digestive system becomes inflamed. This disease cannot be cured permanently.

Hidradenitis Suppurativa: It is a lifelong, painful skin disease that causes scarring and abscesses on the skin.

Infection that has been caused due to HIV or Tuberculosis.

Symptoms of Anal Fistula

The symptoms or signs of an Anal Fistula include:

● Intense and constant pain around the anus that may become worse if you sit down, pass stool, or cough

● Redness and swelling

● Foul smell of the discharge that comes out of the hole near the anus.

● Fever if you have an abscess

● Blood or puss when solid waste exits from your anus

● Struggling while controlling bowel movements in several patients

Complications of Anal Fistula Surgery

Surgery for an anal fistula always carries complications and risks. Complications following surgery include:

  • Infection
  • Irregular bowel movements
  • Recurrence of fistula


An incision into the skin, including the fistulectomy procedure, carries an infection risk. Depending on the surgical technique, fistula procedures may need to be completed in stages. Fistula infections may spread throughout the body and cause systemic infections in such cases.

A fistula infection often requires antibiotic treatment. In severe cases of infection, hospitalization may be necessary to allow intravenous antibiotic administration. If there is a high risk of infection, they can also be used as a prophylactic method.

Bowel Incontinence

Surgical fistulas can damage the muscles in the anal sphincter, especially when they involve the muscles in the sphincter. They control bowel movements by tightening around the anus. During sphincter damage, muscles lose strength. Some bowel control may be lost, leading to faeces leaking from the rectum. It is known as faecal incontinence or bowel incontinence.

It is estimated that 3-7% of all patients who undergo fistula surgery experience this complication. Risks vary depending on the location and type of surgery used to remove the fistula. Those with bowel incontinence and those that notice worsening symptoms are at greater risk. This complication is more likely to happen to women and Crohn’s patients.

Recurrence of the fistula

The fistula may recur after surgery for some people. According to some estimates, recurrence rates range from 7-21%, depending on the type of fistula and how it was removed. For example, fibrin glue has a high recurrence rate. Approximately one-third of patients who undergo other procedures have recurrences. If the fistula recurs, most patients will need another surgery to remove it.

Prevention of Anal Fistulas

You can prevent anal fistulas by following some important preventive measures. To prevent  anal fistulas:

  • One should consume a fiber-rich diet
  • The anal region should be kept dry
  • Passing the stool with ease
  • Exercising regularly will also help.

Diagnosis of Anal Fistula 

If you experience symptoms of an anal fistula, your healthcare provider may refer you to a colon and rectal specialist. In addition to asking about your symptoms, the specialist will also ask about your medical history. Your doctor will check for a fistula opening during your physical exam. A doctor may press on the area to see if it is sore or if pus is coming out. The diagnosis may be made using a variety of methods, including: 

  • Fistula probes: A thin, long probe is guided through the fistula’s outer opening. It may be necessary to inject a special dye to determine where the fistula opens.
  • Anoscope: It is used to examine your anal canal with a special scope.
  • Imaging studies: In ultrasounds, sound waves create an image of the anal area. These tests may also include an MRI, which uses magnets and a computer to create images of the affected area.
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Treatments of the Anal Fistula

Anal fistulas rarely heal if they are not treated on time. Following are the possible treatments to treat anal fistula.

Non-Invasive Treatment

Some patients are lucky enough to be able to treat their condition non-invasively. Your doctor may try several therapies to treat your condition, including:  

  • Fibrin glue

Many people have heard about how glue is used increasingly in medicine – in liquid bandages, for sealing incisions following surgeries, and even to glue fistulas shut. This treatment doesn’t work for every fistula, but it’s usually effective on the ones that do. 

  • Plugs 

Collagen isn’t just for cosmetics anymore. Your doctor may inject collagen into the affected area to seal off a fistula. 

  • Catheters

You might be familiar with urinary catheters – tubes that drain liquid from the bladder. Catheters work much the same way in fistulas. Fistulas that are actively infected usually need these tubes or similar devices to drain the infection.

Treatment  With Medication

  • Antibiotics

All types of bacterial infections can be treated with antibiotics. The infection causing your fistula can also be treated with over-the-counter antibiotics. In addition to stopping an active infection, no medication can eliminate the fistula itself.

  • Stem cells

Using stem cells injected into the fistula to promote repair is one new treatment being tried for Crohn’s patients – ask your doctor for more details and to find out if it might be for you. 

Surgical Procedures 

The surgeon will examine your case and choose the most suitable procedure. Below are the details of these different treatment options. 


The fistulotomy will occur if the fistula is not too near your anus. In this procedure, the doctor will cut open the whole area of the fistula, which involves the skin and muscle only where the fistula is. Due to this treatment, the perianal fistula will heal into a flat scar.

 Fistulotomy is the most suitable treatment for many patients with anal fistula. It is ineffective for those patients whose fistula is passing through a large part of the sphincter muscles because the risk of damaging the control of bowel movement (incontinence) is high in it. Other procedures are recommended by surgeons where the risk of incontinence is high.

Bioprosthetic Plug

It is another option for the treatment of perianal fistula. A bioprosthetic plug is a cone-shaped plug composed of animal tissue (bioprosthetic). This procedure involves inserting the plug into the fistula and stitching its internal opening. 

This treatment has no serious consequences and effectively blocks an anal fistula. 

Seton Treatment

This treatment is recommended by surgeons when the fistula passes through a considerable section of the sphincter muscles. Seton is a surgical thread made up of silicone. It is inserted in the fistula and left there for several weeks. It helps in draining all the anal abscesses.

LIFT Procedure

LIFT stands for Ligation of Intersphincteric Fistula Tract and takes place when fistulotomy is a risk for the patient. In this procedure, the skin above the fistula is cut open, and the sphincter muscles are moved away from each other. The fistula is then sealed from both ends, and the skin between is left open to be healed.

This procedure has recently been developed and had positive results till now. More research is needed for long-term results.

Several other procedures to cure anal fistulas include laser surgery, endoscopic ablation, fibrin glue, and advancement flap procedure. After examining you, your doctor will advise you which procedure suits your case, as all the treatments have pros and cons. 

Treatment follow-up 

Anal fistulas take a good amount of time to heal, so it is necessary to have a follow-up appointment with your doctor. This appointment usually happens after 4 to 8 weeks after your surgery. In this appointment, the doctor ensures you are not getting any other perianal abscesses or fistulas and sees if further surgery is needed.

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When to Consult a Doctor?

Untreated fistulas aren’t pleasant, but they can be more unpleasant than surgery. There’s no shame in seeking help – the high success rate of active treatment should encourage you to seek it. Consult a doctor and get the right diagnosis about anal fistula and get the best treatment. Your doctors online professional doctors can help you get the diagnosis and treat you most suitably and comfortably!

FAQs About Anal Fistula Answered By Your Doctors Online Team

How serious is an anal fistula?

An anal fistula can cause significant discomfort, pain, and complications such as infections and abscesses. If left untreated, an anal fistula can lead to the weakening of the rectum muscles, which can lead to incontinence.

Can a fistula heal on its own?

No, a fistula cannot heal on its own. Treatment is usually necessary to promote healing, reduce the risk of infection and abscesses, and relieve symptoms. Treatment options may include antibiotics, topical ointments, and in some cases, surgery.

Is it OK to live with an anal fistula?

No, it is not advised to live with an anal fistula. It is important to seek medical attention as soon as possible to ensure proper healing and to reduce the risk of infection and abscesses.

Can hemorrhoids cause a fistula?

Yes, hemorrhoids can cause a fistula. A fistula can form when an abscess caused by a hemorrhoid does not heal correctly. The abscess can form a tunnel between the rectum and the skin, called a fistula.

Can fistula be cancerous?

No, fistulas are not cancerous. An infection or an abscess usually causes them and can be very painful. Treatment usually involves draining the abscess or infection and allowing the fistula to heal. Surgery may be needed in some cases.

Do fistulas leak poop?

Yes, fistulas can leak poop. It is usually caused by a tear or a hole in the wall of the rectum that connects to the skin or other organs. It can cause fecal matter to leak out and may require surgery to repair.

Is it hard to poop with a fistula? 

Yes, it can be hard to poop with a fistula. The fistula can cause inflammation and irritation in the rectum, making it difficult to pass stools. Additionally, the inflammation can cause narrowing of the rectum, making it harder to pass stools.

What can be mistaken for a fistula?

Anal abscesses, hemorrhoids, and anal warts can all be mistaken for a fistula. Other conditions such as Crohn’s disease, ulcerative colitis, and diverticulitis can cause similar symptoms and be mistaken for a fistula.

Are fistulas smelly?

Yes, fistulas can be smelly due to pus and other bacteria accumulating in the affected area.

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