A fistula is an abnormal communication between two surfaces, which occurs as a result of an opening in the skin. It can occur spontaneously or as a result of some external agent. Even for the drainage of an abscess.

In the following article we will address anal fistula, the types that exist, the causes that cause it, the symptoms it presents and the treatments applicable in these cases.

What is an anal fistula?

An anal fistula is described as a disease, where fibrous and infected ducts appear that communicate the anus with the skin of the rectum. It can be primary or internal, secondary or external.

Note: It is usually an abnormal communication and is complicated by the presence of abscesses in that region.

In many cases they appear and disappear spontaneously , although there are some that must be drained and others that need surgery. They are more frequent in the male sex with a 2:1 ratio (twice as many cases as women) and usually appear at times of the year with higher temperatures.

Types of anal fistula

The types of anal fistula come through the classification of Sir Alan Parks in 1976, which is the most widely used in the medical area worldwide and is based on the direction that the fistula follows depending on or in relation to the device. sphincteric (1)

Below, we mention and briefly describe them for their identification and recognition if necessary.


They are the most common type of fistula and are relatively the easiest to treat due to the easy access medical personnel have for intervention.

It is the one that occurs in the path between the anal canal and the skin of the perineum , without associating any other type of elements when it is simple, and presenting abscesses in the fatty tissue in secondary cases.

Note: Secondary cases occur in the intersphincteric space with abscesses in the shape of a horseshoe or that branch or cross the ipsilateral midline. (two)


They have a more complex type of intervention and cover the course of the external sphincter to the ischiorectal fossa. It is a descending course and is not usually associated with the presence of abscesses, unless it is of secondary extension.

It is usually characterized and recognized, as it goes towards the flow to end up in the skin of the perianal region. (3)


Together with the extrasphincteric ones, they are those that are usually associated with diseases in patients such as Crohn’s disease or diverticulitis. They have a course that passes over the puborectalis muscle and usually give rise to submucosal fistulas.


These represent 3% of the cases of patients with anal fistula. They are usually produced by external agents, with a path from the rectum towards the perianal area. In fact, in many cases, they tend to be a consequence of the treatment of other types of fistulas.

Causes of an anal fistula

Anal fistula has certain factors that can trigger its appearance. They will be mentioned and described below for your contemplation and recognition.

injuries or wounds

Anal fistulas in the vast majority of cases are usually triggered through injuries or wounds in patients. These wounds can be caused by: external agents, defecation or even a surgical process of another fistula.


An injury, even when it is weak, with poor hygiene can lead to infections that produce an anal fistula.

Important: The infection usually begins in the anal gland and later creates a tunnel-like formation under the skin, which connects from the anus to the inflamed and infected gland.

intestinal disorders

The rupture of the fibrous tissues of the anus , can be produced by lacerating defecations, which are characterized by being thick and hard, since as a first effect their elasticity decreases and produces vulnerability to trauma and the ease of tearing the skin of the anal canal. . (4)

Symptoms of an anal fistula

Anal fistula presents quite characteristic symptoms , which must be recognized and identified if they appear in our body. Below we mention and describe the most relevant symptoms.

pain and inflammation

The pain usually occurs during and after the evacuation of the patients, and is described as intense and with the presence of burning . The pain can persist for minutes or for hours, depending on the level of inflammation that is present.

Note: The swelling is usually in the perianal area, and can be confused with painful external hemorrhoids. These are recognized as perianal fistula.

bleeding and discharge

The bleeding is light and quite frequent . It is usually perceived in toilet paper, in small quantities and bright in color. It can also occur around fecal matter, in the form of a streak. (5)

Itching, redness and irritation

The intensity is variable, but is usually mild. Quite irregular in frequency and appears and disappears spontaneously. In many cases, its appearance is related to prolonged standing , sitting, forced evacuations, and physical exertion, such as exercising.

Treatment to eliminate an anal fistula

For the elimination of an anal fistula in internal medicine, certain types of treatments are applied that, depending on its severity, can complement each other. They will be mentioned and described below.

Surgical intervention

Surgery is recognized as the only truly successful treatment for the removal of anal fistulas. Above all, it applies to those patients for whom drug treatment did not produce favorable results. It is one of the most widely used treatments today for these clinical pictures.

To highlight: The evaluation of the success of the surgery is measured by factors such as: recurrence, delayed healing and postoperative anal incontinence.

Antibiotics, analgesics and anti-inflammatories

For medical treatments, they usually recommend topical anesthetic creams that help with pain relief and reduce inflammation in the area. They must be recognized, located and identified to reduce the risks of recurrences and deformities in the skin and anus.

For their part, antibiotics are techniques aimed at preventing the proliferation of infectious microorganisms and the most commonly used are Metronidazole and Ciprofloxacin .

It is important that they are prescribed by a doctor and under his supervision , to reduce the risk of loss of sensitivity in the area and reappearance after stopping treatment.

Note: Drug treatments are often prescribed when consequences of diseases such as Crohn’s disease are found.

fibrin injection

The technique of injection of adhesives such as fibrin is applied after a washing and curing process . It is one of the most difficult and with the highest risk of presenting postoperative anal incontinence. It is also usually applied in cases of recurrent fissures , mainly of the extrasphincteric and suprasphincteric type.

Key Findings

  • Anal fistula is an abnormal connection between certain areas of the anus and the small glands of the anus.
  • There is a high rate of occurrence, especially in the male sex , much more than in the female. In fact, they are considered twice as many cases.
  • They are consequences of an infection, caused spontaneously, by poor hygiene, by external agents or caused injuries.
  • It is important to recognize the orientation of the infection and its trajectory in order to identify the classification and appropriate treatment.
  • An intestinal disorder that causes evacuation problems may be the reason for the appearance of an anal fistula.
  • Medical treatments must be supervised to avoid the risk of losing sensation in the area and a reappearance of the anal fistula without being noticed.
  • Bleeding and discharge are normal, as long as the amounts are small and bright red.

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