What are the causes of anal fissure? Let’s take a look

Anal fissure is a serious condition. It is not only very painful but can also cause a series of diseases when it is severe. Most anal fissures are caused by infection and constipation. Therefore, in our daily lives, we must pay attention to personal hygiene and always maintain a clean environment to make our bodies healthier.

1. Introduction to Anal Fissure

Although anal fissure causes very small wounds and is limited to the area around the anus, it has a high incidence rate (accounting for 20% of anorectal diseases, second only to hemorrhoids) and is very painful, often presenting as anal tearing pain. It is listed as one of the three most common anorectal diseases along with hemorrhoids and fistulas.

The pathogenic factors of anal fissure are mainly related to local anatomical characteristics, infection and constipation.

2. Local anatomical characteristics of the anal canal

The rectum bends from the back to the front to the anus, and the pressure at the back is relatively high during defecation (as shown in the figure below). In addition, the blood circulation in the middle part of the anal canal is poor and its elasticity is poor. When the stool is dry or contains foreign objects, it is easy to be damaged and not heal. Also, because the muscles around the anus are mainly distributed on both sides of the anal canal, forming a relatively weak point in the middle part of the front and back of the anus, when the stool is dry and difficult to pass, it is easy to tear due to violent expansion, forming local skin cracks. If not treated in time, due to the stimulation of feces and bacterial infection, it will lead to anal canal skin ulcers and form fresh anal fissures. Most fresh anal fissures can be cured by only medication and keeping the local area clean.

Patients with anal fissures will experience burning pain in the anus due to the traction and stimulation of defecation, which is called defecation pain. There may be relief after defecation, which is called the interval period. Then the anal sphincter will spasm due to the stimulation of pain and inflammation, causing severe pain, which may last from a few minutes to a few hours, and may be as long as more than 10 hours. The pain will only be relieved when the sphincter relaxes after fatigue, forming a unique cyclical phenomenon of anal fissure pain.

3. Causes of anal fissure

Because the anal sphincter is in a spasm state for a long time, the muscle contraction compresses the blood vessels, causing local blood circulation disorders, the inflammation is not easy to subside, and even the local skin may form chronic anal fissures due to ischemia and necrosis. Most chronic anal fissures cannot be completely cured by medication alone and require surgical treatment.

Anal fissure patients, fearing pain during defecation, often intentionally prolong the interval between bowel movements, causing the feces to stay in the large intestine too long. The water in the feces is over-absorbed by the large intestine, and the longer the time, the drier the feces, further aggravating constipation. When dry and hard feces are discharged, the damage to the anal fissure wound is further aggravated, forming a vicious cycle of anal fissure pain - fear of defecation - dry and hard feces - aggravation of anal fissure, which makes the anal fissure not heal for a long time.

Therefore, developing good living habits and maintaining smooth bowel movements are the primary tasks in preventing anal fissures. If there is burning pain in the anus during defecation, blood in the stool, or clinical manifestations of constipation, medical treatment should be sought early.