Causes of Hemorrhoids

Hemorrhoids happen as the result of increased pressure within the veins around the anus or lower rectum. Certain risk factors, while not direct hemorrhoid causes, can increase pressure within the hemorrhoidal veins, which can lead to hemorrhoids. These risk factors include straining to move stool, sitting for long periods of time, and eating a low-fiber diet.

What Are the Causes of Hemorrhoids?

Hemorrhoids are veins around the anus or lower rectum that are swollen and inflamed. There are several groups of veins that surround the rectum and anus -- one group is known as internal hemorrhoidal veins, the others are known as external hemorrhoidal veins. The underlying cause of hemorrhoids is increased pressure within these veins. Internal hemorrhoids are caused by increased pressure within the internal hemorrhoidal veins; external hemorrhoids occur when there is increased pressure within the external hemorrhoidal veins.
 

Risk Factors That Can Lead to Hemorrhoids

There are a number of conditions that can increase pressure within the hemorrhoidal veins. While not hemorrhoid causes, they are considered hemorrhoid risk factors. Risk factors are conditions or behaviors that increase your chances of getting a certain disease. It does not mean that everyone with these conditions will develop hemorrhoids, just that the chances are higher.
 
Hemorrhoid risk factors include:
 
  • Straining to move stool, or other poor bowel habits such as sitting for long periods
  • Sitting or standing for long periods of time
  • Pregnancy
  • Aging
  • Chronic constipation or diarrhea
  • Anal intercourse
  • Obesity
  • High-fat, low-fiber diet.
     
Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD
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