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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.


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

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.


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.


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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.