Anal fissure

An anal fissure is a small tear in the tissue that lines the anus or "anal canal" (the opening through which stool passes out of the body). Anal fissures can be painful and may bleed.

What causes an anal fissure?

Anal fissures can be caused by any trauma to the anus or anal canal. An anal fissure typically occurs when you pass hard or large stools during a bowel movement. Anal fissures are also common in women after childbirth and in young infants. Other uncommon causes of anal fissures include scarring in the anorectal area or an underlying problem such as Crohn's disease or ulcerative colitis (types of inflammatory bowel disease), anal cancer, or some infectious diseases including sexually transmitted diseases.

What are the symptoms of an anal fissure?

The typical symptoms of an anal fissure include severe pain during, and especially after, a bowel movement, lasting from several minutes to a few hours. Patients may also notice bright red blood from the anus that can be seen on the toilet paper or on the stool. Between bowel movements, patients with anal fissures are often relatively symptom-free. Many patients are fearful of having a bowel movement and may try to avoid passing a bowel movement because of the pain. Sometimes, a crack or tear in the anus or anal canal can be visible.

How is an anal fissure diagnosed?

Usually your doctor can diagnose an anal fissure by visual inspection of the anus or by gentle exam with the tip of the finger. Sometimes an endoscopy may be done to diagnose the fissure and to rule out other common causes for bleeding and pain in this area, for example hemorrhoids.

What are complications of an anal fissure?

An anal fissure may become chronic. If a fissure does not heal within six weeks it is considered chronic and may need further treatment. Anal fissures may also recur. Once you've experienced an anal fissure, you are prone to having another one. A tear that extends to surrounding muscles is another possible complication of an anal fissure. It may extend into the ring of muscle that holds your anus closed (internal anal sphincter), making it more difficult for the fissure to heal. An unhealed fissure can trigger a cycle of discomfort that may require medications or surgery to reduce the pain and to repair or remove the fissure.

How are anal fissures treated?

An anal fissure often heals on its own within four to six weeks. If it doesn't, medical treatment is usually tried first before surgery is recommended. The goal of treatment is to lower the pressure on the anal canal by making stools soft as well as easing the discomfort and bleeding.

Treatments may include the following:

  • Preventing constipation through the use of stool softeners, increased intake of fluids while avoiding caffeine-containing products (which cause dehydration), and dietary adjustments (increase in intake of high fiber foods and fiber)
  • Soaking in a warm bath (also called a sitz bath), 10 to 20 minutes several times a day, to promote the relaxation of the anal muscles
  • Cleansing the anorectal area more gently
  • Avoiding straining or prolonged sitting on the toilet
  • Using petroleum jelly to help lubricate the anorectal area

The conservative practices mentioned above heal most fissures (80 to 90 percent) within several weeks to several months. However, when treatments fail and anal fissures persist or recur other measures can be tried, including:

  • Using hydrocortisone-containing suppositories, foams, or creams to reduce inflammation
  • Applying other creams and ointments -- a medicated cream (to help heal the fissure), a topical muscle relaxant (to relax the anal muscles), an anesthetic ointment (to reduce pain, if pain interferes with having a bowel movement), nitroglycerin or calcium channel blocker ointments (to relax the anal muscles and increase blood flow to the region, promoting healing)
  • Injecting botulinum toxin type A (Botox) into the anal sphincter. The injection temporarily paralyzes the anal sphincter muscle, relieving pain and promoting healing
  • Surgery-If you have a chronic anal fissure that is resistant to other treatments, or if your symptoms are severe, your doctor may recommend surgery. Surgery usually involves cutting a small portion of the anal sphincter muscle to reduce spasm and pain and promote healing. This type of surgery is usually very safe and has only a small risk of causing incontinence. The surgery can usually be performed without an overnight stay. Pain is often relieved after a few days and complete healing is achieved in a few weeks.

Can anal fissures be prevented? 

Keeping the anorectal area dry and wiping the area with soft materials, a moistened cloth, or cotton pad while avoiding rough toilet paper may help prevent anal fissures. All occurrences of severe constipation or persistent diarrhea should be promptly treated. Fissures in infants may be prevented by frequent diaper changes and prompt treatment of constipation.