Read below about swollen rectum, including causes, treatment options and remedies. Or get a personalized analysis of your swollen rectum from our A.I. health assistant. At Buoy, we build tools that help you know what’s wrong right now and how to get the right care.

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Swollen Rectum Symptoms

The rectum (and in association, the anus) is an often-overlooked part of the body. However, rectal symptoms, such as swelling, can signal serious underlying disease. The rectum is the last part of the colon (large intestine). It is where stool is held before it passes out of the anus — the body part that controls the expulsion of feces. See this image for a visual representation of the rectum and anus in relation to the colon.

These parts of the body are in such close communication that often swelling in the rectum can manifest as symptoms involving in the anus. Often conditions in this area are described as "anorectal" [1,2].


For example, symptoms of a swollen rectum may include:

Since a swollen rectum or anus can signal serious underlying disease, it is important to recognize all the associated symptoms in order to get appropriate medical care and follow-up.

Swollen Rectum Causes Overview

The communication that leads from the rectum to the anus is called the anal canal. The anal canal is composed of muscles (sphincters) that control the passing of feces from the rectum through the anus. There is an internal sphincter and an external sphincter. See this image for a visual representation of this anatomy.

In addition to these muscles, the anorectal area is composed of glands, arteries, veins, and nerves that control sensation and flow of fluid and blood in that area.

Conditions that affect these components can result in swelling and its associated symptoms. It is important to make an appointment with your physician in order to discuss the possible causes of your symptoms.


Vascular causes can lead to a swollen rectum, such as damaged or stressed veins. The veins in your anorectal area can become congested and swollen due to increased pressure from actions such as straining during bowel movements or conditions such as pregnancy. Swollen veins within the rectum are called internal hemorrhoids while swollen veins under the skin of the anus are called external hemorrhoids [3]. See this image for a representation of the different kinds of hemorrhoids.


Proctitis is any condition that involves inflammation of the lining of the rectum. Proctitis often involves symptoms of pain and problems with defecation that can lead to swelling of the rectum [4].

  • Infection: Infections of this area, in the form of sexually transmitted infections and foodborne illness, are a frequent cause of proctitis. If these infections involve the glands of the anal canal, abscesses (areas filled with pus) can develop, leading to swelling and increased pain in the anorectal area.
  • Inflammatory medical conditions: Inflammatory bowel disease (Crohn's disease or ulcerative colitis) often involve the rectum. These conditions can lead to chronic irritation that results in anal abscesses that cause pain and swelling.


Anatomical causes may lead to a swollen rectum, such as the following.

  • Fistula: Rarely, an abnormal anatomical communication, or fistula, can form between the anus or rectum and the skin around the anus [5]. An anal fistula is often a result of an anal abscess that did not heal, leading to breaks in the surface of the skin.

  • Prolapse: Increased pressure in combination with a weakening of the muscles of the anal canal can lead to a condition in which the rectum "slides" through the anus and protrudes through the opening. This is called a rectal prolapse [6]. The prolapse can often look and feel like a swollen lump, as in this image.


A malignant mass in the anal canal can grow and swell leading to associated symptoms of pain,bleeding and/or itching in the anorectal area. Anal cancer rarely metastasizes (spreads) to other parts of the body.

A.I. Health Assistant Causes for Swollen Rectum

The list below shows results from the use of our A.I. Health Assistant by Buoy users who experienced swollen rectum. This list does not constitute medical advice.

  1. 1.Hemorrhoids

    Hemorrhoids are a very common condition that affects more 50% of the population, typically after the age of 30. Hemorrhoids are enlarged, bulging blood vessels in the anus that can bleed or clot.

    Chronic and can worsen with time. But, 90% of people are successfully managed with non-surgical treatments.

    Top Symptoms:
    constipation, rectal pain, rectal bleeding, pain when passing stools, anal itching
    Symptoms that never occur with hemorrhoids:
    unintentional weight loss

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  2. 2.Chronic or Recurrent Hemorrhoids

    Hemorrhoids are a very common condition that affects more 50% of the population, typically after the age of 30. Hemorrhoids are the "varicose veins of the anus and rectum" - enlarged, bulging blood vessels in the anus that can bleed or clot.

    Chronic hemorrhoids can worsen with time. But, 90% of people are successfully managed with non-surgical treatments.

    Top Symptoms:
    rectal bleeding, rectal pain, pain when passing stools, anal itching, painless rectal bleeding
    Symptoms that never occur with chronic or recurrent hemorrhoids:
    unintentional weight loss
  3. 3.Cellulitis

    Facial cellulitis is a skin infection that typically comes from other parts of the face like the mouth or the sinuses and needs antibiotic treatment. Symptoms can be pain, redness, warmth and swelling of the affected area.

    Dependent on severity of infection

    Top Symptoms:
    fever, chills, facial redness, swollen face, face pain
    Symptoms that always occur with cellulitis:
    facial redness, area of skin redness
    Primary care doctor

Swollen Rectum Treatments and Relief

Although this is a concerning issue, there are several effective home remedies that may help resolve your symptoms. If the swelling worsens or persists, however, you should consult your physician promptly.

At-home treatments

Sometimes a swollen rectum is the result of lifestyle habits that can be easily modified in order to prevent symptoms. For example:

  • Diet modifications: Eating high-fiber foodssuch as fruits, vegetables, and whole grains can soften the stool and help prevent straining that often causes hemorrhoids. You can also obtain your daily dose of fiber from over-the-counter supplements such as Metamucil. Drinking an adequate amount of water can also help to keep the stools soft and regular, especially if you decide to take fiber supplements [7].
  • Exercise: Staying active can help prevent constipation and reduce pressure on the veins that lead to hemorrhoids. Losing excess weight can also reduce extra pressure on the anorectal area.
  • Do not strain or sit too long on the toilet: Both activities can increase pressure in the veins of the rectum and anus, leading to hemorrhoids.
  • Practice safe sex: Getting tested regularly and using condoms can prevent sexually transmitted infections that can cause infection and abscess formation in the anorectal area.

Medical treatments

If these lifestyle changes do not help to resolve your symptoms, your rectal swelling may be due to a more serious cause such as inflammatory bowel disease or cancer. See your physician immediately if you notice symptoms that persist. Your physician may suggest treatment such as:

  • Anti-inflammatory drugs: These types of drugs are often the first step in the treatment of inflammatory bowel disease. Your physician may also use immune system-suppressing drugs to reduce substances that may trigger inflammation.
  • Antibiotics: Depending on the type of infection/presence of an abscess, your physician may prescribe antibiotics to heal fistulas and subsequent abscesses.
  • Combined chemotherapy and radiation: For anal cancer, your physician will begin treatment with a combination of chemotherapy and radiation to improve chances of cure.
  • Surgery: Surgery is the primary treatment for conditions such as rectal prolapse, but is also used for the treatment of early-stage anal cancers.

Questions Your Doctor May Ask About Swollen Rectum

  • Q.Have you had any changes in your weight?
  • Q.Do your symptoms worsen when sitting?
  • Q.Do you have a history of constipation?
  • Q.Do you have a rash?

If you've answered yes to one or more of these questions, try our swollen rectum symptom checker to find out more.

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Swollen Rectum Symptom Checker Statistics

  • People who have experienced swollen rectum have also experienced:

    • 15% Rectal Pain
    • 11% Anal Itching
    • 8% Constipation
  • People who have experienced swollen rectum had symptoms persist for:

    • 38% Less Than a Week
    • 23% Over a Month
    • 21% Less Than a Day
  • People who have experienced swollen rectum were most often matched with:

    • 66% Cellulitis
    • 16% Hemorrhoids
    • 16% Chronic or Recurrent Hemorrhoids
  • Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

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  1. Foxx-Orenstein AE, Umar SB, Crowell MD. Common Anorectal Disorders. Gastroenterology & Hepatology. 2014;10(5):294-301. NCBI Link
  2. Wald A, Bharucha AE, Cosman BC, Whitehead WE. Management of Benign Anorectal Disorders. American Journal of Gastroenterology. 2014;109:1141-1157. ACG Link
  3. Lohsiriwat V. Hemorrhoids: From Basic Pathophysiology to Clinical Management. World Journal of Gastroenterology. 2012;18(17):2009-2017. NCBI Link
  4. Symptoms & Causes of Proctitis. National Institute of Diabetes and Digestive and Kidney Diseases. Published August 2016. NIDDK Link
  5. Overview: Anal Fistula. NHS. Updated August 6, 2016. NHS Link
  6. Rectal Prolapse Expanded Version. American Society of Colon and Rectal Surgeons. ASCRS Link
  7. Pendick D. 6 Self-Help Tips for Hemorrhoid Flare-Ups. Harvard Medical School: Harvard Health Publishing. Updated October 26, 2018. Harvard Health Publishing Link