Hemorrhoids are swollen veins in the lower rectum. They often subside on their own or with treatment from over-the-counter products. But in rare cases, hemorrhoids can become infected.

Prolapsed internal hemorrhoids are more likely to become infected due to blood flow issues. Procedures, such as rubber band litigation and surgical removal, can also increase the risk for infection.

An infected hemorrhoid requires medical treatment to reduce the chances of complications. Read on to learn about what causes infected hemorrhoids, and how to treat them.

In some cases, certain types of hemorrhoids and hemorrhoid treatments can lead to infections.

Hemorrhoids are more likely to become infected when healthy blood flow to the area is restricted. Healthy blood flow to the rectal area means a steady supply of white blood cells and certain proteins that are part of the immune system. This helps lower the risk of infection.

Internal hemorrhoids seldom become infected. An internal hemorrhoid is one that forms in the rectum. This is the portion of the large intestine that ends at the anus.

Sometimes, an internal hemorrhoid may push down from the rectum, which is known as a prolapsed internal hemorrhoid.

A prolapsed internal hemorrhoid can often be gently pushed back up into the wall of the rectum. But it’s still more likely than other types to become infected.

This is because blood flow to the vein can be cut off. This is known as a strangulated internal hemorrhoid. Without the nutrients, oxygen, and immune-system cells carried in the bloodstream, an infection can quickly form.

You may have a higher risk of a strangulated hemorrhoid and a subsequent infection if you have a condition that reduces healthy circulation to the rectum. Among the conditions that can cause reduced blood flow to the region are:

In addition, having HIV or another condition that weakens the immune system can increase the risk for infected hemorrhoids.

Infections can also develop after procedures that treat hemorrhoids. In particular, rubber band ligation can sometimes lead to infection.

In this procedure, the doctor places a band around the hemorrhoid, cutting off its blood supply. The hemorrhoid will soon fall off and the skin will heal. During this process, however, the affected tissue is vulnerable to infection from the bacteria in your intestine.

A similar risk follows surgery to remove a hemorrhoid (hemorrhoidectomy), which is usually done if a rubber band ligation is not successful.

All the typical symptoms of hemorrhoids may be present if you have infected hemorrhoids. These symptoms include:

  • small amounts of blood in the toilet or on your bathroom tissue after a bowel movement
  • swelling around the anus
  • itching in and around the anus
  • pain, especially when sitting or straining during a bowel movement
  • a lump under the skin around your anus.

But an infection can bring on other symptoms, too. Signs of infection include:

  • fever
  • pain that gets worse, even after standard hemorrhoid treatment
  • redness around the anus, especially near the site of the infection

If you suspect a hemorrhoid has become infected, see a doctor. An infection can lead to serious complications, such as peritonitis. This is a potentially life-threatening infection of the abdominal wall and internal organs.

To diagnose a hemorrhoid infection, your doctor will review your medical history and your current symptoms. Symptoms such as fever, can help your doctor make a diagnosis.

A physical examination will also be done to check for visual signs of infection, such as redness around the hemorrhoid. If you have a prolapsed internal hemorrhoid, your doctor may decide to remove it before it gets infected.

Blood tests, like a white blood cell count, are also done if an infection is suspected. A low WBC can indicate an infection. Additional tests, such as a urinalysis or X-rays, may be done to look for infections that have spread to other parts of the body.

An antibiotic, such as doxycycline (Doxteric), is used to treat an infected hemorrhoid or infected tissue caused by a procedure to remove a hemorrhoid.

Antibiotics prescribed for peritonitis include cefepime (Maxipime) and imipenem (Primaxin). The specific type of antibiotic you’re prescribed will depend on the severity of your infection and any problems or allergies you may have with certain medications.

Surgery to remove infected tissue around the hemorrhoid, or tissue within the abdomen (if the infection has spread), may be necessary in severe cases. This is called debridement and can help the body heal from an infection.

In addition to medications and possible surgical procedures, home remedies may help relieve symptoms. These include:

  • ice packs or cold compresses around your anus
  • oral pain relievers, such as acetaminophen (Tylenol) or ibuprofen (Advil)
  • pads that contain a numbing agent.

Also, adjusting your diet can lead to less straining during bowel movements. A diet that includes high-fiber foods, such as fruits, vegetables, and whole grains, can help keep your stool soft and add bulk and reduce straining.

Always check with your doctor before trying any type of home treatment. You don’t want to risk spreading the infection or interfering with the medical treatment you’re receiving.

The best way to prevent an infected hemorrhoid is to avoid getting any kind of hemorrhoid. In addition to a high-fiber diet — 20 to 35 grams daily — and plenty of fluids, you can help prevent hemorrhoids by:

  • maintaining a healthy weight
  • avoiding sitting for hours at a time
  • exercising regularly, including aerobic activity, such as brisk walking, tennis, or dancing
  • going to the bathroom as soon as you need to, because delaying a bowel movement can make the stool more difficult to pass

If you have a hemorrhoid, you can lower your infection risk by seeing a doctor as soon as you have symptoms.

Mild symptoms may be treatable with over-the-counter pads and ointments, as well as good hygiene and soaking in a warm sitz bath. Following your doctor’s advice is essential in making sure the treatment is effective, and reducing your chances of an infection.

If you’re prescribed antibiotics after a procedure, take the entire course of medications and don’t stop early. If you have side effects from the antibiotics, call your doctor’s office and see if an alternative drug may work.

The severity of the infection will determine how long it takes to clear up and if treatment will require more than antibiotics. A weeklong course of doxycycline may be enough, but a serious infection may require a longer course or additional medications.

Following up with your doctor during treatment will reduce your odds of complications.

If you have a personal or family history of hemorrhoids, you’re more likely to develop hemorrhoids in the future. However, having an infected hemorrhoid once doesn’t mean a subsequent hemorrhoid is any more likely to become infected. The key is to pay attention to symptoms and treatment early on.

If you do develop symptoms of a prolapsed internal hemorrhoid, you should see a doctor. And if you’re unsure whether you have an infected hemorrhoid, err on the side of caution and go see your doctor.