Anal Abscess

Medically Reviewed by Poonam Sachdev on January 21, 2025
Written by Rick Ansorge, Peg Rosen
10 min read

An anal abscess is a painful, pus-filled lesion that forms in or near your anus, rectum, or the area between your genitals and anus. Depending upon its cause, location, and your doctor’s choice of terminology, your condition may also be referred to as an: 

  • Anorectal abscess
  • Rectal abscess
  • Ischiorectal abscess
  • Intersphincteric abscess
  • Supralevator abscess
  • Perirectal abscess
  • Gland abscess

Almost 90% of all anal abscesses are caused by blocked glands that become infected. The most common type of anal abscess is a perianal abscess, which typically appears as a painful swelling near the opening of your anus (the section at the end of your digestive tract where poop leaves your body). A perianal abscess may be red and feel warm when touched.

Perirectal abscesses are located inside the rectum (the section where poop is held in your digestive tract before it passes through the anus). This type of abscess is less common and often associated with inflammatory bowel diseases (IBDs), such as Crohn’s disease.

Surgical incision and drainage is the most common treatment for all types of anal abscesses and is usually successful.

Perianal abscess vs. anal fistula

As much as 50% of patients with an anal abscess will develop a complication called a fistula. A fistula is a small tunnel that makes an abnormal connection between the inside of your anus and your skin.

Fistulas usually develop when anal glands become infected. Your body creates the fistula as a way to drain pus from the infection. Pus-filled anal abscesses that result from infected anal glands cause 75% of anal fistulas.

Symptoms of anal fistulas include pain, swelling, itching, and redness around the anus. In some cases, fluids — including pus, poop, and blood — may drain from the fistula opening in your skin. In other cases, the opening of the fistula to the skin can become blocked. This may lead to recurrent anal abscesses.

Most fistulas need to be treated surgically. Fistulas can develop before or after an abscess is treated.

Anal abscesses have many different causes. These include:

  • Blocked anal glands
  • Anal fissures (tears in the anal canal) that become infected
  • Sexually transmitted diseases and other infections
  • Trauma to the anus or rectum
  • Perianal hidradenitis suppurativa, an inflammatory condition affecting the anal glands 
  • Infections of tissue lining the anal canal (often related to IBD)

Risk factors for anal abscess

Risk factors for anal abscesses include:

  • Being the receptive partner in anal sex
  • Insertion of foreign objects into the rectum (such as sex toys)
  • Being assigned male at birth
  • Cigarette smoking
  • Diverticulitis
  • Chronic diarrhea and constipation
  • Colitis (inflammation of the colon), often due to an infection
  • IBDs such as Crohn's disease or ulcerative colitis
  • Diabetes
  • Pelvic inflammatory disease
  • Pregnancy
  • Certain immune-suppressing medications, such as prednisone and chemotherapy drugs
  • Radiation therapy
  • Cancer

Symptoms of superficial perianal abscesses can include:

  • Pain, which is usually constant, throbbing, and worse when sitting down
  • A painful lump near your anus
  • Skin irritation around your anus, including swelling, redness, and tenderness
  • Discharge of pus from your anus or near your anus
  • Rectal bleeding
  • Constipation or pain associated with bowel movements
  • Lower abdominal pain
  • Flu-like symptoms such as chills and fever

Deeper anorectal abscesses may not be as painful as superficial abscesses and are not externally visible. But they can cause:

  • Fever
  • Chills
  • Fatigue/low energy
  • Lower abdominal pain

Hemorrhoids and abscesses can develop in the same general area of your body. They can both be painful, itchy, and sensitive to the touch. But they are very different conditions.

Unlike abscesses, hemorrhoids aren’t infections. They’re veins, similar to varicose veins, that have become swollen and twisted. 

There are two types of hemorrhoids:

  • Internal hemorrhoids form inside the rectum. You often can’t see or feel them, but sometimes they bulge out through the anus. 
  • External hemorrhoids form under the skin around your anus. 

How can you tell if you have an abscess or hemorrhoid? While an anal abscess will feel raised, fluid-filled, and warm to the touch, hemorrhoids appear as purplish, solid bumps. Since hemorrhoids aren’t infections, they don’t cause fever and chills like an abscess might.

Treatment options for hemorrhoids and abscesses are also very different. In most cases, hemorrhoids go away on their own, often with the help of simple treatments, such as warm compresses and over-the-counter ointments. Abscesses, on the other hand, usually need to be surgically drained by a doctor.

Usually, a primary care doctor or specialist can diagnose an anal abscess by doing a clinical evaluation.

During your visit, your practitioner will ask about your symptoms, take a health history, and visually examine your external anal area. They will also probably do a digital rectal exam, which involves inserting a lubricated, gloved finger into your anus and rectum to check for abnormalities.

In some cases, a doctor may want to do a more comprehensive rectal exam in an operating room with anesthesia. They may also perform or order additional testing to better understand your condition or to screen for other health issues such as sexually transmitted diseases, rectal cancer, IBD, and diverticular disease. 

These procedures may include:

Anoscopy. A lighted device called an anoscope is gently inserted and then expanded inside the rectum, allowing for a clear and broad view of the area. You might feel some pressure during the procedure, and if your doctor chooses to take a small piece of tissue for examination (a biopsy), you may feel a brief, sharp pinch.

Ultrasound, CT scan, or MRI. These imaging studies are sometimes used by doctors to diagnose deeper abscesses and to visualize fistula tunnels.

Proctosigmoidoscopy. This test involves inserting a flexible tube with a light and camera into the rectum and anus. Your doctor may do it to find the source of bleeding and to rule out other health issues, such as cancer.

Colonoscopy. Using a flexible tube with a camera and light on one end, a physician can examine your large intestine. This procedure would likely be done to assess or screen for other conditions, such as IBD.

It’s important to see a doctor if you think you might have an anal abscess. In most cases, they will want to drain the abscess surgically.

If your doctor, however, recommends that you first try treating the abscess at home, the following measures might help. They can also ease some of your discomfort as you await an appointment to have your abscess drained. (Under any circumstances, don't try to drain the abscess yourself, as this could risk infection and serious injury.)

Warm compresses. Soak a small, clean towel with warm water. Apply the compress to the abscess for 15-20 minutes, two or three times a day or as needed.

Sitz baths. A sitz bath is a warm, shallow soak for your buttocks and genitals. It can be very soothing and help heal anal abscesses and other conditions in this area of your body, such as fistulas and hemorrhoids. You can buy a sitz bath kit that can be fitted to your toilet. You can also take a shallow soak in a very clean bathtub. Some doctors recommend taking a sitz bath after each bowel movement or at least two to three times a day when you have an anal abscess. 

Careful post-rupture wound care. If your abscess ruptures, you can develop a worse or new infection. To minimize this risk, gently clean the area with soap and water, cover the wound with a bandage, and change your bandages regularly. Watch your wound carefully, and if you see any signs of infection, call your doctor.

Surgical drainage

In most cases, prompt surgical drainage, ideally before your abscess erupts, is the go-to treatment for an anal abscess. Doctors can usually drain superficial anal abscesses in their office using a local anesthetic. Large or deeper anal abscesses may require hospitalization and the help of an anesthesiologist.

In all likelihood, your drainage incision won’t need stitches. Bandaging may not even be necessary or advantageous. In certain cases, such as when abscesses are very large, doctors may place a catheter at the wound site so it can drain continuously.

After abscess or fistula surgery, your discomfort should be mild and you can expect to lose only a minimal amount of time at work or school.

The following can help ease any discomfort you might have and encourage healing during your recovery:

Pain medication. Depending upon the type of procedure you’ve had, your doctor might want you to have prescription pain medication or simply recommend over-the-counter analgesics such as acetaminophen. If you have very little discomfort, you might not need to take anything.

Antibiotics. If an abscess is particularly large or if you have a preexisting health issue such as diabetes or decreased immunity, your doctor might prescribe antibiotics to guard against an infection. Be sure to take the entire course of these drugs, even if you feel fine and are pain-free. 

Laxatives. Bowel movements may be uncomfortable during the healing process. Your doctor might recommend that you take a laxative, which will soften your stool and make it easier to go to the bathroom.

Sitz baths. Sitting in a shallow tub of clean warm water several times a day can be very soothing, help keep the surgical site clean, and can encourage healing. Commercially sold sitz bath kits can be fitted to your toilet. You can also take a shallow soak in a clean bathtub.

Will perianal abscess go away on its own?

In the vast majority of cases, anal abscesses need to be surgically drained to heal properly and safely. However, in rare circumstances, an abscess may heal without surgical drainage.

Whatever the case may be, the decision isn’t one to make on your own. It’s important to see a doctor as soon as you have symptoms since improperly managed abscesses can lead to dangerous and even life-threatening infections.

Once they do an examination, your doctor can determine what the safest and most effective course of treatment will be for you.

Without prompt treatment, an anal abscess can lead to complications, which can be severe. These include:

  • Continued or worsened pain
  • Infection that spreads to the blood (sepsis)
  • Abscess growth
  • Return of the abscess if it appears to heal on its own
  • Fistula
  • Incontinence
  • Fournier’s gangrene, a rare, life-threatening bacterial infection 

Surgical incision and drainage of anal abscesses is often successful. Like most procedures, however, complications are possible. These include:

Infection/sepsis. This is a particular risk for patients with compromised immune systems 

Anal fistula. About 40% of patients develop an anal fistula after their abscess is drained, especially within the first year of the procedure. The fistula can then cause recurrent abscesses, so surgery to remove the fistula is necessary. If a fistula is detected at the outset, the fistula will be removed at the same time the abscess is drained. Fistula surgery is typically done in a hospital setting.

Abscess recurrence. It’s not uncommon for an abscess to return after it has been drained. This is often due to the formation of an anal fistula. For this and other reasons, it’s important to schedule and keep follow-up doctor appointments.

Anal fissures. These are small, painful tears or cuts in the skin around the anus.

Damage or trauma to anal nerves. This is rare but can result in fecal incontinence.

Scarring. The incision may lead to scarring in the area around the anus.

An anal abscess, sometimes called an anorectal abscess, is a painful pus-filled pocket that forms under the skin in or near your anus or rectum. About half of people with an anal abscess also develop an anal fistula, which is an abnormal tunnel that drains pus from the inside of your anus to the skin. It’s important to see a doctor if you have pain or leakage in your anal area because abscesses rarely go away on their own and can lead to serious infections and other complications. Surgical incision and drainage is the best way to treat anal abscesses in most cases and is usually successful.

How does a perianal abscess go away?

In most cases, perianal abscesses don’t go away on their own. They usually must be surgically drained by a doctor. 

Is it a fistula or an abscess?

An anal abscess is a tender lump in or near the anus or rectum that you can often see or feel with your fingers. A fistula is an abnormal tunnel that forms between an abscess inside your anus or rectum and the skin near your anus. If you are feeling or looking for something, you will probably not easily feel or see a fistula “hole.” You may, however, be in pain and notice that you seem to be “leaking” pus, blood, or poop. In many cases, you could be dealing with both an abscess and a fistula, as they often occur together. 

What is the difference between a pilonidal sinus and a perianal abscess?

An anal abscess is a painful pus-filled lump that forms under the skin near your anus or rectum. A pilonidal sinus is a small, abnormal opening inside your butt cheeks. When the sinus becomes infected, it will form a painful cyst that is typically filled with pus, hair, and dead skin.