Hemorrhoids are dilated, twisted (varicose) veins located in the wall of the rectum and anus.
Hemorrhoids occur when the veins in the rectum or anus become enlarged. Hemorrhoids that form above the junction between the anus and rectum (anorectal junction) are called internal hemorrhoids. Hemorrhoids that form below the anorectal junction are called external hemorrhoids. Both internal and external hemorrhoids may remain in the anus or protrude outside the anus.
Increased pressure in the veins of the anorectal area leads to hemorrhoids. This pressure may result from pregnancy, frequent heavy lifting, or repeated straining during bowel movements (defecation). Constipation may contribute to straining. In a few people, hemorrhoids develop from increased blood pressure in the portal vein.
External hemorrhoids form a lump on the anus. If a blood clot forms (called a thrombosed external hemorrhoid), the lump becomes quite painful and more swollen. 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 (pruritus ani―see Anal and Rectal Disorders: Anal Itching) is usually not a symptom of hemorrhoids, but itching may develop if hemorrhoids make proper cleansing of the anal region difficult.
External hemorrhoids may become inflamed or develop a blood clot. Internal hemorrhoids may bleed.
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) or sigmoidoscope (a flexible tube used to view the lower portion of the large intestine, the rectum, and the anus) helps a doctor determine whether the person has a more serious condition, such as a tumor. People who have bleeding from the rectum often require a sigmoidoscopy or colonoscopy.
Usually, hemorrhoids do not require treatment unless they cause symptoms. Taking stool softeners or a bulking type of laxative (such as psyllium) may relieve straining with bowel movements. Symptoms can sometimes be relieved by soaking the anus in warm water in what is known as asitz bath. The soaking is accomplished by squatting or sitting in a partially filled tub or using a container filled with warm water placed on the toilet bowl or commode. 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. Alternatively, especially when the pain is severe, a doctor may inject a local anesthetic and cut out the blood clot, which sometimes relieves the pain more rapidly.
Bleeding hemorrhoids can be treated with an injection of a substance that causes scar tissue to form and obliterate the hemorrhoids. This procedure is called injection sclerotherapy.
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. The treatment is usually applied to one hemorrhoid at a time at intervals of 2 weeks or longer. Internal hemorrhoids may also be destroyed with a laser (laser destruction), an infrared light (infrared photocoagulation), or an electrical current (electrocoagulation).
Surgery to remove the hemorrhoids may be used if other treatments do not work. However, hemorrhoid surgery may result in severe pain, as well as urine retention and constipation. Less painful techniques are being investigated, such as Doppler-guided hemorrhoid artery ligation, in which hemorrhoid arteries are identified and tied off, thus reducing the blood supply to the hemorrhoids. Another technique is called circumferential stapled hemorrhoidopexy, in which a circular surgical stapler is used to remove or resuspend protruding hemorrhoids, but its advantages and indications have yet to be defined.
Last full review/revision May 2012 by Parswa Ansari, MD