Hofer - Liebl - Specialists in Visceral Surgery and Proctology

Anal fissure (anal tear)

Causes, forms, treatment

Pain and bleeding during bowel movements

The most common cause of pain and bleeding during defecation is anal fissure, also called anal tear or anal fissure. This is the name given to a longitudinal tear in the transition zone of the tender skin of the anal canal (anoderm) to the outer skin. Anal fissure is one of the most common reasons why patients consult a proctologist.

Anal fissure is almost always a benign, curable condition. The exact incidence is not known, because according to a representative survey, 87.5% of people with anorectal symptoms never see a doctor. Women seem to be affected slightly more often.

A distinction is made between the acute and chronic forms. Depending on the stage and extent of the symptoms, conservative or surgical treatments are used. We adhere to the current guideline anal fissure of the professional societies.

Chronic anal fissure is a common cause of blood in the stool and of pain
Anatomical model of a chronic anal fissure with secondary changes (1 hypertrophic anal papilla, 2 deep crypts, 3 anal fissure, 4 outpost fold).

Mechanical and inflammatory causes

How does an anal fissure develop?

Cause of anal fissure: Hard stool

The mucous membrane of the anal canal can be affected and tear whenever the area is too stressed. A variety of different circumstances such as stress, unbalanced diet or antibiotic treatments can become the trigger for an anal fissure such as

  • Stool too hard (constipation)
  • diarrhoea
  • Too much pressing during bowel movement
  • Too much elongation of the area (anal intercourse)

Cause of anal fissure: cryptitis and subanodermal fistula

If the anal mucosa (anoderm) is already damaged, as in the case of enlarged haemorrhoids or inflammation of the anal glands (cryptitis), a chronic wound can occur even with normal bowel movements. These glands open into the small pockets (crypts, (2) in the illustration) at the transition from the intestinal mucosa to the anal skin. If the glands are inflamed, a superficial fistula tract can form under the anal skin, which then breaks open in the area of the fissure (3). 

Cause of anal fissure: High sphincter pressure?

The opinion that a pathologically increased sphincter pressure is the cause of anal fissure is widespread among doctors and in the specialist literature. The association of anal fissures with high sphincter pressure can be proven by pressure measurement (sphincter manometry). As a result, there is a reduction in blood flow, which in turn hinders healing.

In contrast, the muscle tension can also be explained as a consequence of the painful condition. It is rare to find high sphincter pressure without underlying pain. And when you see how much an anal fissure can bleed, you don't really believe in the reduced blood flow.

Conversely, this tension contributes to the wound edges being pressed together after the bowel movement is complete. Measures to relax can therefore help the wound to clean itself better and thus heal from the depths.

Cause of anal fissure: After operations

Wound healing disorders after anal surgery for other reasons, for example haemorrhoids or anal thrombosis, can also end in chronic wounds resembling a spontaneously developed chronic anal fissure. We see this as an argument to perform any surgery on the anus only if one has no (good) therapeutic alternative and the patient's level of suffering is high.

How you recognise the disease

Symptoms anal fissure

Patient information anal fissure as PDF
Our info flyer on anal fissure

Out of the blue: Acute anal fissure

Acute anal fissure looks like a cut. Typically, an anal fissure is accompanied by a sharp or burning pain during defecation ("... as if there were a shard of glass in the stool..."). After defecation, this pain usually subsides quickly.

The second leading symptom is bright red, fresh bleeding. The intensity of the bleeding ranges from a trace of blood on the paper to dramatic-looking splashes of blood in the toilet. The actual blood loss is nevertheless small and not dangerous.

Many patients also only have either bleeding or pain and not both symptoms. Often the symptoms subside quickly without specific treatment and the initial shock is quickly forgotten.

The outer extension of the acute anal fissure can usually be seen on examination when the buttocks are spread slightly. Almost all anal fissures are found in the midline and 75-90% on the side facing the coccyx ("6 o'clock in lithotomy position SSL", i.e., on examination in the gynecological chair). Patients often perceive the pain maximum accentuated towards the left side, even if the wound is in the middle.

In the case of fissures lateral to the midline ("atypical fissures"), one must also think of infections such as HIV, tuberculosis, and syphilis, of tumors, and of chronic inflammatory bowel diseases such as Crohn's disease. In this case, the guideline recommends "adapted further diagnostics with serological and microbiological examinations as well as colonoscopy with removal of tissue samples (biopsy)."

Good times, bad times: Chronic anal fissure

If periods without symptoms alternate with periods in which the symptoms recur, the disease is probably chronic.

Also, if the pain is dull, delayed after defecation and lasts for hours, this indicates the development of a chronic anal fissure. Patients often report that the pain radiates towards the coccyx.

Other complaints that may develop in the course are itching, anal dampness, traces of blood on the toilet paper, constipation with incomplete emptying of the rectum and increased flatulence.

Externally visible signs of chronic anal fissure are skin thickening or skin folds called outpost fold or guardian mariske. Some patients feel a palpable hardening. Internal growths in the area of the anal papillae (1) are called hypertrophic papillae. These tissue proliferations are caused by local tissue hormones that are actually intended to help heal wounds.

In chronic anal fissure, it is not uncommon to see the exposed internal sphincter muscle at the bottom of the wound.

Since these typical symptoms also occur in other proctological diseases such as the coccyx fistula, an exact diagnosis of anal fissure is important.

Image of a chronic anal fissure with secondary changes
Image of a chronic anal fissure: The deep wound as well as the outpost fold and anal papilla are clearly visible

Conservative or surgical?

Treatment anal fissure

Despite unfavourable conditions in the wound area (intestinal bacteria, constriction, moisture, mechanical stress), 75% of anal fissures surprisingly usually heal by themselves or with simple, caring measures such as relaxing sitz baths.

If pain and bleeding disappear quickly, the patient forgets the unpleasant episode and does not seek further clarification. It is not uncommon for the wound to be closed only superficially, but in the depth of the tear, chronic inflammation develops due to contamination with the ever-present intestinal bacteria.

If the scar is not stable and tears open again and again even in normal stools, outpost folds and growths of the mucous membrane (hypertrophic anal papilla) develop. These skin lobules are often thought to be a hemorrhoid or a polyp. They can assume considerable size and emerge from the anus. Over time, the niche can deepen more and more, in which stool particles and bacteria settle, which further irritate the mucous membrane.

Conservative therapy

Treatment of anal fissure without surgery