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Last Updated: Mar 1, 2019


Hemorrhoids form when the bundle of veins in the anus and lower rectum become enlarged and fall out of place (prolapse). Hemorrhoidal tissue, which consists of blood vessels, connective tissue, and some muscle, is actually a normal part of human anatomy. More accurately, it is the enlargement of hemorrhoids that causes discomfort.

Hemorrhoids are classified into two types: internal and external. Internal hemorrhoids develop inside the lower rectum and anus beneath the mucosa lining and are generally painless. External hemorrhoids show up as lumps around the anus and may cause severe pain. Treatment varies depending on the symptoms and diagnosis, and usually does not require surgery. In the U.S. it is estimated that 4.4% of adults suffer from hemorrhoids - the majority being 45-65 years old.

Causes and Risk Factors

Activities that exert pressure on the vein clusters in the anus and lower rectum (also called anal cushions) are believed to cause enlarged hemorrhoids. Even the upright human posture is often blamed as a contributing factor.

  • Irregular bowel movement. Constipation, excessive straining during a hard bowel, and sitting on the toilet for extended periods are all associated with symptomatic hemorrhoids. These activities can disrupt blood flow to anal cushions, and lead to bulging and prolapse of internal hemorrhoids, or blood clotting in external hemorrhoids. Chronic diarrhea and overuse of laxatives and enemas may also exacerbate these symptoms.
  • Pregnancy. Symptomatic hemorrhoids are common during pregnancy because the expanding uterus pushes against the anal cushions. This condition is temporary and usually resolves itself after birth.
  • Age. As the body ages, the tissues supporting hemorrhoids can weaken, allowing prolapse.


The most common symptoms of hemorrhoids are pain and bleeding during a bowel movement. Other symptoms vary depending on clinical classification.

  • Internal hemorrhoids are generally pain-free, even when some bleeding is observed. Prolapsed tissue that falls out of the anus can be felt by hand, and may be associated with pain and itching. Large internal hemorrhoids can produce the sensation of rectal fullness.
  • External hemorrhoids are bluish lumps that can be seen or felt by hand. They are associated with more pain due to their highly sensitive overlying skin, and can bleed if broken. Blood clotting in external hemorrhoids causes severe pain, and once dissolved, leaves behind loose skin (skin tags).

Diagnosis and Treatment

Diagnosing hemorrhoids involves medical history and physical exams. The perineal area is visually inspected for external hemorrhoids, skin tags, inflammation, and prolapsed tissue. A digital exam, where two fingers are inserted into the rectum, may be performed to look for blood or other irregularities. A short tubular instrument called an anoscope is often inserted in the rectum to visualize hemorrhoidal tissue and assess the anal canal. If blood is observed in the stool, a colonoscopy may be performed in order to rule out colorectal cancer and other more serious conditions.

Pain and discomfort associated with mild hemorrhoidal disease can be treated with at-home remedies. More severe cases require band ligation or surgery.

  • At-home remedies. A high-fiber diet and routine exercise soften stools and promote regularity. These habits help avoid constipation and the need to strain during a bowel movement. A sitz bath, which is a warm water bath for the buttocks, and various topical over-the-counter creams can soothe enlarged hemorrhoids and lessen discomfort. Severe pain associated with blood clotting in external hemorrhoids may require minor surgery.
  • Rubber band ligation. Band ligation can completely eliminate internal hemorrhoids and is very effective at preventing recurrence. During this out-patient procedure, a small elastic band is placed around the hemorrhoid to stop blood flow. Following several treatments over 6-8 weeks the swollen tissue shrinks and falls off. Coagulation treatments work similarly by using laser or heat, but are less effective.
  • Hemorrhoidectomy. When hemorrhoid symptoms persist or worsen in spite of other treatments, surgery is needed. During a hemorrhoidectomy, the affected blood vessels are removed via an incision around the hemorrhoid. Although this operation is an out-patient procedure, it is performed under general anesthesia and requires a short recovery period. Both internal and external hemorrhoids can be removed by hemorrhoidectomy, with a very small chance of recurrence.
  • Stapling. Stapled hemorrhoidopexy is a more recent technique where prolapsed internal hemorrhoids are stapled back to their original position. This procedure is less painful than a traditional hemorrhoidectomy and allows quicker recovery, but is generally considered less effective.


Maintaining regularity and soft stools is the best ways to prevent symptomatic hemorrhoids. This can be achieved with a high-fiber diet, adequate hydration, and regular exercise. Avoiding prolonged sitting and strain during a bowel movement also prevents excess pressure on the anal cushions.


  • “Hemorrhoids”. American Society of Colon and Rectal Surgeons (ASCRS). ASCRS. Retrieved Mar 31, 2014.
  • “Hemorrhoids: Expanded Version”. American Society of Colon and Rectal Surgeons (ASCRS). ASCRS. Retrieved Mar 31, 2014.
  • “Hemorrhoids and what to do about them”. Harvard Health Publications. Harvard Medical School. Retrieved Mar 31, 2014.
  • Lohsiriwat, V. Hemorrhoids: From basic pathophysiology to clinical management. World J Gastroenterol. 2012. 18:2009-17.

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Tina Shahian, PhD

Tina is a writer for Innerbody Research, where she has written a large body of informative guides about health conditions.


A communication specialist in life science and biotech subjects, Tina’s successful career is rooted in her ability to convey complex scientific topics to diverse audiences. Tina earned her PhD in Biochemistry from the University of California, San Francisco and her BS degree in Cell Biology from U.C. Davis. Tina Shahian’s Linkedin profile.


In her spare time, Tina enjoys drawing science-related cartoons.