4 most common cause(s)
Swollen rectum symptoms explained
The rectum (and the anus) are often-overlooked body parts until there is an issue, of course. Rectal symptoms, such as swelling, can signal a 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 stool. 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 swelling in the rectum can often manifest in the anus. Often conditions in this area are described as "anorectal".
Common characteristics of a swollen rectum
For example, symptoms of a swollen rectum may include:
- Pain only during defecation
- Itching or irritation in the anal region
- Palpable lumps or bumps in your anal region
- Blood in your stools/bleeding during bowel movements
- Mucous or discharge in your stools
- Diarrhea
- Tenesmus: This is a frequent urge to have a bowel movement.
Since a swollen rectum or anus can signal a serious underlying disease, it is important to pay attention to your symptoms and seek appropriate medical care.
What causes a swollen anus?
Rectal anatomy
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
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.
Inflammatory causes
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.
- 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 involves the rectum. These conditions can lead to chronic irritation that results in anal abscesses that cause pain and swelling.
Anatomical causes
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. 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. The prolapse can often look and feel like a swollen lump, as in this image.
Cancerous causes
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.
3 swollen rectum conditions
The list below shows results from the use of our quiz by Buoy users who experienced swollen rectum. This list does not constitute medical advice and may not accurately represent what you have.
Chronic or recurrent hemorrhoids
Chronic, or recurrent, hemorrhoids are swollen veins in the anus and rectum that never really resolve and may be symptomatic more or less constantly.
Hemorrhoids are caused by anything that puts pressure on the anus from the inside, such as straining during bowel movements; constipation; pregnancy; or anal intercourse.
Most susceptible are pregnant women and older people, though anyone can be affected.
Symptoms include a small amount of bleeding during or after a bowel movement, as well as discomfort, itching, or swelling around the anus.
A medical provider can suggest treatment to ease the symptoms of chronic hemorrhoids, as well as make certain of the diagnosis since other, more serious conditions can have symptoms similar to hemorrhoids.
Diagnosis is made through patient history and physical examination.
Treatment most often involves simple lifestyle changes such as drinking more water; adding fiber-rich foods to the diet; using fiber supplements and stool softeners; not delaying, or straining, to pass a bowel movement; and using topical medications. Surgical procedures to remove the hemorrhoid can be used in some cases.
Rarity: Common
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
Urgency: Self-treatment
Hemorrhoids
Hemorrhoids, or "piles," are swollen veins in the anus or rectum. They may be located inside the rectum (internal) or outside the body at the anus (external.)
The condition is caused by straining during bowel movements and/or from increased pressure during pregnancy and childbirth.
Hemorrhoids are a common occurrence, especially in older people. Pregnant women are susceptible, as is anyone who has chronic constipation or is obese.
Symptoms include discomfort, pain, pressure, and itching. There may be small amounts of bleeding during bowel movements, though some hemorrhoids cause no symptoms at all.
Severe pain can indicate a thrombosed hemorrhoid, meaning a clot has formed within it. This is not serious but the pain can be debilitating and requires treatment right away. Also, rectal bleeding can also be a sign of more serious diseases such as diverticulitis or cancer and should always be diagnosed by a medical provider.
Diagnosis is made through physical examination and sometimes through colonoscopy.
Treatment begins with good hygiene, cold compresses, and over-the-counter pain relievers. Surgery may be done for some cases.
Colonic neoplasm
Colonic neoplasm means "new tissue" growing in the colon, or large intestine. This neoplasm may be either benign (not cancerous) or malignant (cancer.)
The exact cause of any cancer remains unknown. Risk factors seem to be:
- Being over fifty years of age.
- Family history of the disease.
- A high-fat, low-fiber diet, typical in the modern world
- Chronic inflammatory diseases of the colon such as Crohn's disease.
- Smoking and alcohol use.
- Diabetes, obesity, and inactivity.
The earliest symptoms are usually polyps, small growths within the colon which can be detected on colonoscopy and removed before they can become cancerous. Later symptoms may be unexplained fatigue; change in bowel habits; persistent abdominal discomfort such as gas or cramps; blood in stool; or rectal bleeding.
Diagnosis is made through colonoscopy and sometimes blood testing.
Treatment is done through surgery, which may be minor or extensive; and through chemotherapy with radiation therapy, usually done before and after surgery. Supportive care to keep the patient comfortable is also an important part of treatment.
Cellulitis
Cellulitis is a bacterial infection of the deep layers of the skin. It can appear anywhere on the body but is most common on the feet, lower legs, and face.
The condition can develop if Staphylococcus bacteria enter broken skin through a cut, scrape, or existing skin infection such as impetigo or eczema.
Most susceptible are those with a weakened immune system, as from corticosteroids or chemotherapy, or with impaired circulation from diabetes or any vascular disease.
Symptoms arise somewhat gradually and include sore, reddened skin.
If not treated, the infection can become severe, form pus, and destroy the tissue around it. In rare cases, the infection can cause blood poisoning or meningitis.
Symptoms of severe pain, fever, cold sweats, and fast heartbeat should be seen immediately by a medical provider.
Diagnosis is made through physical examination.
Treatment consists of antibiotics, keeping the wound clean, and sometimes surgery to remove any dead tissue. Cellulitis often recurs, so it is important to treat any underlying conditions and improve the immune system with rest and good nutrition.
Rarity: Uncommon
Top Symptoms: fever, chills, facial redness, swollen face, face pain
Symptoms that always occur with cellulitis: facial redness, area of skin redness
Urgency: Primary care doctor
Anal fissure
An anal fissure is a break, or tear, in the mucous membrane lining of the anus. The anus is the opening at the end of the digestive tract where stool leaves the body.
A fissure is caused primarily by constipation, which leads to straining to pass large hard stools; trauma caused by insertion of objects or by anal sex; and illnesses such as any type of inflammatory bowel disease or sexually transmitted disease.
Symptoms include pain and bleeding during and after a bowel movement; discomfort and difficulty with urination; and a visible tear, resembling a crack, in the anal tissue that may have a foul-smelling discharge.
Diagnosis is made through physical examination.
Treatment primarily involves relieving constipation, and the straining it causes, by adding fiber and more fluids to the diet; and easing anal irritation by soaking in a warm bath and gently cleansing the tissues of the anus. In some cases, medicated creams or suppositories may be prescribed.
At-home and medical treatments for a swollen anus
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.
At-home treatments
A swollen rectum is sometimes the result of lifestyle habits that can be easily modified in order to prevent symptoms.
- Diet modifications: Eating high-fiber foods such 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.
- 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 sitting and straining 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 infections or abscesses 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, 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.
- Surgery: Surgery is the primary treatment for rectal prolapse as well as early-stage anal cancers.
Questions your doctor may ask about swollen rectum
- Have you had any changes in your weight?
- Do your symptoms worsen when sitting?
- Do you have a history of constipation?
- Do you have a rash?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
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References
- Foxx-Orenstein AE, Umar SB, Crowell MD. Common Anorectal Disorders. Gastroenterology & Hepatology. 2014;10(5):294-301. NCBI Link
- Wald A, Bharucha AE, Cosman BC, Whitehead WE. Management of Benign Anorectal Disorders. American Journal of Gastroenterology. 2014;109:1141-1157. ACG Link
- Lohsiriwat V. Hemorrhoids: From Basic Pathophysiology to Clinical Management. World Journal of Gastroenterology. 2012;18(17):2009-2017. NCBI Link
- Symptoms & Causes of Proctitis. National Institute of Diabetes and Digestive and Kidney Diseases. Published August 2016. NIDDK Link
- Overview: Anal Fistula. NHS. Updated August 6, 2016. NHS Link
- Rectal Prolapse Expanded Version. American Society of Colon and Rectal Surgeons. ASCRS Link
- Pendick D. 6 Self-Help Tips for Hemorrhoid Flare-Ups. Harvard Medical School: Harvard Health Publishing. Updated October 26, 2018. Harvard Health Publishing Link