Merck Manual

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Parswa Ansari

, MD, Hofstra Northwell-Lenox Hill Hospital, New York

Reviewed/Revised Jan 2023
Topic Resources

Hemorrhoids are dilated, twisted blood vessels located in the wall of the lower rectum and anus.

  • The swollen vessels are caused by an increase in pressure.

  • Lumps form inside or outside of the anus, which can cause pain or bleeding.

  • The diagnosis is based on an examination of the anus and rectum, often with an anoscope, sigmoidoscope, or colonoscope.

  • Most hemorrhoid symptoms go away without treatment, but fiber, stool softeners, and sitz baths can help relieve them.

  • Some hemorrhoids are treated with a rubber band procedure, injection sclerotherapy, or infrared photocoagulation or sometimes surgery.

The rectum is the section of the digestive tract above the anus where stool is held before it passes out of the body through the anus.

The anus is the opening at the end of the digestive tract where stool leaves the body.

Hemorrhoids occur when the blood vessels in the lower rectum or anus become enlarged.

Internal hemorrhoids are hemorrhoids that form above the junction between the anus and rectum (anorectal junction).

External hemorrhoids are hemorrhoids that form below the anorectal junction.

Both internal and external hemorrhoids may remain in the anus or protrude outside the anus.

Causes of Hemorrhoids

Increased pressure in the vessels of the anorectal area leads to hemorrhoids. This pressure may result from pregnancy, frequent heavy lifting, or repeated straining during bowel movements (defecation). Constipation Constipation in Adults Constipation is difficult or infrequent bowel movements, hard stool, or a feeling that the rectum is not totally empty after a bowel movement (incomplete evacuation). (See also Constipation... read more may contribute to straining.

Symptoms of Hemorrhoids

External hemorrhoids form a lump on the anus. If a blood clot forms (called a thrombosed external hemorrhoid), the lump becomes larger and is more painful and more swollen than a hemorrhoid that is not thrombosed.

Internal hemorrhoids often do not cause a visible lump or pain, but they can bleed. Bleeding from internal hemorrhoids typically occurs with bowel movements, causing blood-streaked stool or toilet paper. The blood may turn water in the toilet bowl red. However, the amount of blood is usually small, and hemorrhoids rarely lead to severe blood loss or anemia.

Hemorrhoids may discharge mucus and create a feeling that the rectum is not completely emptied after a bowel movement. Itching in the anal region (anal itching Anal Itching Itching of the anus (the opening at the end of the digestive tract where stool leaves the body) and the skin around the anus (perianal skin) is called anal itching or pruritus ani. (See also... read more or pruritus ani) is usually not a symptom of hemorrhoids, but itching may develop if hemorrhoids make proper cleansing of the anal region difficult.

Complications of hemorrhoids

Hemorrhoids may become inflamed or thrombosed. Internal hemorrhoids may bleed.

Diagnosis of Hemorrhoids

  • A doctor's examination

  • Anoscopy

  • Sometimes sigmoidoscopy or colonoscopy

A doctor can readily diagnose swollen, painful hemorrhoids by inspecting the anus and rectum.

An examination with an anoscope (a short, rigid tube used to view the rectum) is done to evaluate painless or bleeding hemorrhoids. People who have bleeding from the rectum may require a sigmoidoscopy or colonoscopy (see Endoscopy Endoscopy Endoscopy is an examination of internal structures using a flexible viewing tube (endoscope). In addition to examinations, doctors can use endoscopy to do biopsies and give treatment. Endoscopes... read more ) to rule out a more serious condition, such as a tumor.

Treatment of Hemorrhoids

  • Stool softeners and sitz baths

  • For external thrombosed hemorrhoids, removal of blood clot

  • For internal hemorrhoids, injection sclerotherapy, rubber band ligation, or infrared photocoagulation

  • Sometimes surgical removal

Usually, hemorrhoids do not require treatment unless they cause symptoms. Taking stool softeners or bulking the stools with fiber supplements (such as psyllium) may relieve straining with bowel movements. Hemorrhoid symptoms can sometimes be relieved by soaking the anus in warm water in what is known as a sitz bath. The soaking is accomplished by squatting or sitting for 10 to 15 minutes in a partially filled tub or using a container filled with warm (not hot) water placed on the toilet bowl or commode.

For external thrombosed hemorrhoids, especially those that cause severe pain, a doctor may inject a local anesthetic Local anesthesia and regional anesthesia Surgery is the term traditionally used to describe procedures (called surgical procedures) that involve manually cutting or stitching tissue to treat diseases, injuries, or deformities. However... read more to numb the area and cut out the blood clot or hemorrhoid, which sometimes relieves the pain more rapidly.

Taking acetaminophen or a nonsteroidal anti-inflammatory drug (NSAID) can help alleviate the pain of a thrombosed hemorrhoid. Local anesthetic ointments or witch hazel compresses also may help. Pain and swelling usually diminish after a short while, and clots disappear over 4 to 6 weeks.

For bleeding internal hemorrhoids, a doctor can inject a substance that causes scar tissue to form and destroy the hemorrhoids. This procedure is called injection sclerotherapy. An alternative to injection sclerotherapy is infrared photocoagulation. During this procedure, an infrared light is used to treat bleeding hemorrhoids.

Large internal hemorrhoids and those that do not respond to injection sclerotherapy can be tied off with rubber bands (a procedure called rubber band ligation). The band causes the hemorrhoid to wither and drop off painlessly. One hemorrhoid is treated about every 2 weeks.

Banding a Hemorrhoid

Some internal hemorrhoids are removed by tying them off with rubber bands in an outpatient procedure called rubber band ligation. The instrument used (ligator) consists of forceps surrounded by a cylinder with ¼-inch (½-centimeter) rubber bands placed on one end. The ligator is inserted into the anus through an anoscope (a short, rigid viewing tube), and the hemorrhoid is grasped with the forceps. The cylinder is slid upward over the forceps and the hemorrhoid, pushing the rubber bands off the cylinder and around the base of the hemorrhoid. The rubber bands cut off the hemorrhoid's blood supply, causing it to wither and drop off painlessly in a few days. One hemorrhoid is ligated about every 2 weeks. Several treatments may be required. Sometimes, multiple hemorrhoids can be ligated at a single visit.

Banding a Hemorrhoid

Surgery to remove the hemorrhoids may be used if other treatments do not work. However, hemorrhoid surgery (called hemorrhoidectomy) may result in severe pain, as well as urine retention and constipation.

Another technique is called circumferential stapled hemorrhoidopexy, in which a circular surgical stapler is used. This technique causes less pain after it is done, but it may result in a higher rate of complications than conventional surgical hemorrhoidectomy, and hemorrhoids may return.

Other methods to destroy internal hemorrhoids, such as Doppler-guided hemorrhoid artery ligation, are being tried. In this method, hemorrhoid arteries are identified using ultrasonography and tied off with a suture, thus reducing the blood supply to the hemorrhoids.

Treatments using lasers, freezing probes, or an electrical current (electrocoagulation) are unproved. Rubber band ligation is still the standard treatment.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Fiber Therapy, GenFiber , Geri-Mucil, Hydrocil , Konsyl, Metamucil, Metamucil MultiHealth, Mucilin , Natural Fiber Laxative, Natural Fiber Therapy, Reguloid
7T Gummy ES, Acephen, Aceta, Actamin, Adult Pain Relief, Anacin Aspirin Free, Aphen, Apra, Children's Acetaminophen, Children's Pain & Fever , Children's Pain Relief, Comtrex Sore Throat Relief, ED-APAP, ElixSure Fever/Pain, Feverall, Genapap, Genebs, Goody's Back & Body Pain, Infantaire, Infants' Acetaminophen, LIQUID PAIN RELIEF, Little Fevers, Little Remedies Infant Fever + Pain Reliever, Mapap, Mapap Arthritis Pain, Mapap Infants, Mapap Junior, M-PAP, Nortemp, Ofirmev, Pain & Fever , Pain and Fever , PAIN RELIEF , PAIN RELIEF Extra Strength, Panadol, PediaCare Children's Fever Reducer/Pain Reliever, PediaCare Children's Smooth Metls Fever Reducer/Pain Reliever, PediaCare Infant's Fever Reducer/Pain Reliever, Pediaphen, PHARBETOL, Plus PHARMA, Q-Pap, Q-Pap Extra Strength, Silapap, Triaminic Fever Reducer and Pain Reliever, Triaminic Infant Fever Reducer and Pain Reliever, Tylenol, Tylenol 8 Hour, Tylenol 8 Hour Arthritis Pain, Tylenol 8 Hour Muscle Aches & Pain, Tylenol Arthritis Pain, Tylenol Children's, Tylenol Children's Pain+Fever, Tylenol CrushableTablet, Tylenol Extra Strength, Tylenol Infants', Tylenol Infants Pain + Fever, Tylenol Junior Strength, Tylenol Pain + Fever, Tylenol Regular Strength, Tylenol Sore Throat, XS No Aspirin, XS Pain Reliever
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