An anal fissure is an anal tear or crack, in the lining of the anal canal, a cut or tear in the anus that extends into the anal canal.
It can cause pain during and after a bowel movement and there may be blood in the stool.
Most anal fissures are less than one centimeter across, but the anus is a highly sensitive part of the body. As a result, a pain in this region can be quite severe, even with a small tear.
In this article we will cover the symptoms, diagnosis, and treatment of anal fissures, and cover way in which they can be prevented.
Fast facts on anal fissures
Here are some key points about anal fissures. More detail and supporting information is in the main article.
damage to the lining of the anus is a common cause
in some cases they are idiopathic (no known cause)
approximately 10 percent of people are affected in their lifetime
staying hydrated may help prevent anal fissures
A common symptom of anal fissures is blood in stool.
The main signs and symptoms of an anal fissure include:
Pain – especially when passing stools. During the passing of a stool the pain is sharp, and then afterward there may be a longer deep burning sensation. Fear of pain may put some patients off going to the toilet, increasing their risk of constipation.
If the person delays using the bathroom, this can make the pain and the tear worse, because the stools will be harder and larger. Some people may experience a sharp pain when they clean themselves with toilet paper.
Blood – because the blood is fresh, it will be bright red and may be noticed on the stools or the toilet paper. Anal fissures in infants commonly bleed.
Itching – in the anal area. The sensation may be intermittent or persistent.
Dysuria – discomfort when urinating (less common). Some patients may urinate more frequently.
Anal fissure can happen for a number of reasons.
Constipation – large, hard feces (stools) are more likely to result in lesions in the anal area during a bowel movement than soft and smaller ones.
Diarrhea – repeated diarrhea can cause an anal fissure to develop.
Muscle spasms – experts believe that anal sphincter muscle spasms may increase the risk of developing an anal fissure. A spasm is a brief, automatic jerking muscle movement, when the muscle can suddenly tighten. Muscle spasms may also undermine the healing process.
Pregnancy and childbirth – pregnant women have a higher risk of developing an anal fissure towards the end of their pregnancy. The lining of the anus may also tear during childbirth.
STIs (sexually-transmitted infections) – also known as STDs (sexually transmitted diseases) are linked to a higher risk of having anal fissures. Examples include syphilis, HIV, HPV (human papillomavirus), herpes and Chlamydia.
Underlying conditions – some underlying conditions, such as Crohn’s disease, ulcerative colitis, and other inflammatory bowel diseases may cause ulcers to form in the anal area.
Anal sex – can in rare instances cause anal fissures.
Two muscular rings (sphincters) control the anus – the outer ring is consciously controlled; the inner ring is not. The inner sphincter is under constant pressure. Experts believe that, if the pressure gets too much, the inner sphincter might spasm, reducing blood flow, increasing the risk of a fissure.
Anal fissures can affect people of any age or sex equally. It is the most common cause of rectal bleeding in babies and children. Some children may find the sight of bright red blood in stools and toilet paper distressing.
In most cases, anal fissures resolve without the need for medical treatment or surgery. Topical creams, suppositories, or both, and OTC painkillers may help with symptoms. Some people, however, may experience chronic problems if the lesion fails to heal correctly.
An anal fissure that lasts less than 6 weeks is called an acute anal fissure. A chronic anal fissure has symptoms for longer than 6 weeks. A primary anal fissure has no identifiable cause, while a secondary anal fissure does have an identifiable cause.