What Causes Anal Fissures?

Medically Reviewed by Carol DerSarkissian, MD on October 19, 2020

An anal fissure is a cut or a tear in the thin, delicate lining of your anus.

The tear often exposes the muscle around the anus, called the anal sphincter. The damage can cause that muscle to spasm, which can pull apart the edges of the fissure even more. The spasms can cause pain and slow down the healing. Bowel movements can also keep the fissures from getting better.

An anal fissure is considered acute if it recently happened or if you've had it less than 6 weeks. It's considered chronic if it's been more than 6 weeks or it comes back often.

Who Gets Anal Fissures?

These tears are common, although you might think the pain and bleeding are symptoms of other conditions, like hemorrhoids. They can happen to both men and women. They can also happen to babies.

Adults between 20 and 40 are most likely to get them. But you can have them at any age, even though your risk generally goes down as you get older.

Anal fissures are seen more often with certain medical conditions, such as:

  • Anal cancer
  • Leukemia
  • STDs and HIV
  • Complications from other conditions, like Crohn’s or ulcerative colitis

Why Do People Get Anal Fissures?

They're caused by trauma or injury that stretches your anal canal. Reasons for this can include:

Less often, having anal sex or putting things into your anus can overstretch the skin and cause a fissure.

Too much pressure, tight anal sphincter muscles, and poor blood supply to your anus may lead to their development and poor healing.

Anal fissures don't usually give way to more serious problems. They don’t cause cancer. But they can be very uncomfortable.

To help these fissures heal and keep them from coming back:

  • Eat a healthy diet that has plenty of fiber.
  • Stay well-hydrated.
  • Avoid being constipated.
WebMD Medical Reference



American Society of Colon & Rectal Surgeons: "Anal Fissure." 

Cleveland Clinic: "Anal Fissures." 

UpToDate: "Patient information: Anal fissure (Beyond the Basics)."

NHS Choices: "Anal fissure - Introduction," "Anal fissure - Prevention."

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