About - An anal fistula is an abnormal tunnel or passage that develops between the inside of the anus or rectum and the skin around the anus. It most commonly develops after an anal abscess, which is a collection of pus caused by infection of an anal gland. When an anal abscess drains, either naturally or after treatment, a small channel may remain between the infected gland and the skin. If this tunnel does not heal properly, it can develop into a chronic anal fistula. Anal fistulas usually do not heal completely on their own and may require a surgical procedure for definitive treatment. Early evaluation by a qualified doctor can help prevent recurrent infection and other complications.
The most common cause of an anal fistula is an infection of an anal gland. The infection can lead to an anal abscess. When the abscess drains, a tract may remain between the anal canal and the skin, forming a fistula. Other possible causes include:
Previous anal abscess
Crohn’s disease
Inflammatory bowel disease
Tuberculosis
Certain sexually transmitted or other infections
Previous surgery or injury involving the anal or rectal area
Radiation treatment to the pelvic region
Diverticular disease in some cases
Certain cancers, although this is uncommon
In many people, the exact underlying cause cannot be identified beyond a previous anal gland infection or abscess.
An anal abscess is a collection of pus caused by an infection near the anus. It commonly causes sudden pain, swelling, tenderness, and sometimes fever. An anal fistula is a tunnel that may develop after an abscess has drained or been treated. It connects the anal canal or rectum with the skin. An abscess generally requires drainage when significant pus has accumulated, while a fistula often requires a procedure to close or remove the abnormal tract.
A doctor can often diagnose an anal fistula based on the person’s symptoms and a physical examination. During the examination, the doctor may look for:
An external opening near the anus
Swelling or redness
Drainage of pus or blood
Tenderness
Signs of a recurrent abscess
In some cases, the fistula opening may be difficult to identify or the tract may extend deeper into the tissues. Additional tests may therefore be recommended. Depending on the situation, investigations may include:
Digital rectal examination
Anoscopy or proctoscopy
Pelvic MRI
Endoanal ultrasound
Other imaging or examinations when an underlying disease such as Crohn’s disease is suspected
An MRI can be particularly useful for identifying the course and extent of a complex fistula.
Anal fistulas can be classified according to their relationship with the muscles that control bowel movements, known as the anal sphincter muscles.
Some common types include:
Intersphincteric fistula: Passes between the internal and external sphincter muscles.
Transsphincteric fistula: Passes through portions of the sphincter muscles.
Suprasphincteric fistula: Extends above the external sphincter before reaching the skin.
Extrasphincteric fistula: Passes outside the sphincter complex and is relatively uncommon.
The classification is important because treatment must balance removal or closure of the fistula with preservation of normal bowel control.
The appropriate treatment depends on the location and complexity of the fistula, the amount of sphincter muscle involved, and whether conditions such as Crohn’s disease are present.
Most persistent anal fistulas require a surgical procedure for definitive treatment. Common procedures include:
Fistulotomy: The fistula tract is opened along its length so that it can heal from the inside outward. This is commonly used for simple fistulas that involve little of the anal sphincter.
Seton placement: A thin surgical thread called a seton may be placed through the fistula tract. It can help maintain drainage and may be used for fistulas that involve a significant amount of sphincter muscle.
Advancement flap: A flap of healthy tissue is used to cover the internal opening of the fistula. This may be considered when preserving the sphincter is particularly important.
LIFT procedure: The ligation of the intersphincteric fistula tract (LIFT) procedure involves identifying and closing the fistula tract between the sphincter muscles. It may be used for selected transsphincteric fistulas.
Other techniques may also be considered depending on the anatomy and complexity of the fistula.
If the fistula is associated with Crohn’s disease or another underlying condition, treatment may involve medicines as well as surgical management. Antibiotics may be prescribed in selected situations, particularly when there is significant infection or an associated abscess. However, antibiotics alone generally do not eliminate an established anal fistula.
You should consult a healthcare professional if you have:
Persistent pain around the anus
A lump or swelling near the anus
Repeated anal abscesses
Pus or blood draining from an opening near the anus
A wound near the anus that does not heal
Persistent irritation or discharge around the anal area
Seek urgent medical attention if severe anal pain is accompanied by fever, chills, rapidly increasing swelling, or feeling seriously unwell, as these may indicate an abscess or spreading infection.
A gastroenterologist may also be involved when Crohn’s disease or another gastrointestinal condition is suspected. An infectious-disease specialist may be considered when a specific unusual infection is suspected.
Most established anal fistulas do not heal permanently without treatment. The external opening may temporarily close, but the underlying tract can remain and cause another abscess or recurrent drainage.
An anal fistula is usually treatable, but an untreated fistula can cause repeated infections, abscesses, pain, and persistent discharge. Complex fistulas require careful treatment because of their relationship with the anal sphincter muscles.
Pain can occur, particularly when an abscess is present. Some fistulas cause relatively little pain but produce persistent pus or blood-stained discharge.
Antibiotics may be useful for treating certain infections associated with a fistula, but they generally do not eliminate the established fistula tract. Definitive treatment may require surgery or another procedure.
Yes. Recurrence is possible, particularly with complex fistulas. The likelihood depends on factors such as the fistula’s anatomy, underlying disease, and the treatment used.
Not all anal fistulas can be prevented. Prompt treatment of an anal abscess and appropriate management of conditions such as Crohn’s disease may reduce the risk of complications.
Medical Disclaimer:This information is intended for general educational purposes and should not be considered a substitute for professional medical advice, diagnosis, or treatment. If you have symptoms suggestive of an anal fistula, consult a qualified healthcare professional for an appropriate evaluation and treatment plan.
