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.
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.
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.
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 (pruritus ani―see Anal Itching) is usually not a symptom of hemorrhoids, but itching may develop if hemorrhoids make proper cleansing of the anal region difficult.
Hemorrhoids may become inflamed or thrombosed. 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) is done to evaluate painless or bleeding hemorrhoids. People who have bleeding from the rectum may require a sigmoidoscopy or colonoscopy (see Endoscopy) to rule out a more serious condition, such as a tumor.
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 for 10 to 15 minutes in a partially filled tub or using a container filled with warm 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 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.
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.
Other methods to destroy internal hemorrhoids are being tried). Using an infrared light (infrared photocoagulation) appears to be effective. Treatments using lasers, freezing probes, or an electrical current (electrocoagulation) are unproved. Rubber band ligation is still the standard treatment.
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. Less painful techniques are being investigated, such as Doppler-guided hemorrhoid artery ligation, in which hemorrhoid arteries are identified using ultrasonography and tied off with a suture, 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. This technique causes less pain after it is done, but it may result in a higher rate of complications and hemorrhoids may recur.
Last full review/revision October 2014 by Parswa Ansari, MD