What Causes Internal Hemorrhoids?

What Are Internal Hemorrhoids?

Hemorrhoids are cushions of blood vessels and tissue inside the rectum that help control bowel movements. Everyone has them. They only become a problem, known as hemorrhoidal disease, when the veins inside swell and become irritated. Internal hemorrhoids sit above the anal canal, in an area with very few pain nerves. That is why they rarely hurt, even though they can bleed. Unlike external hemorrhoids, which form under the skin around the anus, internal hemorrhoids are not visible unless they prolapse, or push through the anal opening.¹

What Causes Internal Hemorrhoids to Develop?

Internal hemorrhoids develop when ongoing pressure builds up in the veins of the lower rectum. That pressure can come from several everyday habits and life stages.

Straining and Constipation

Straining during a bowel movement is one of the most common causes of internal hemorrhoids. Hard stools from constipation force the rectal veins to stretch and swell. Frequent diarrhea can have a similar effect.²

Low-Fiber Diet and Dehydration

A diet low in fiber makes stool harder and more difficult to pass. Not drinking enough water adds to the problem. Both factors increase straining, which raises pressure on the veins in the rectum.

Pregnancy and Added Abdominal Pressure

A growing uterus places direct pressure on the pelvic veins. Hormonal changes during pregnancy can also slow digestion, which can lead to constipation. This combination is why internal hemorrhoids are common during pregnancy and shortly after delivery.

Prolonged Sitting

Sitting for long stretches, especially on the toilet, lets blood pool in the rectal veins. Scrolling on a phone while sitting on the toilet can extend this pressure without a person realizing it.

Aging and Weakened Tissue

As people age, the tissue that supports the rectal veins can weaken and stretch. This makes prolapsed hemorrhoids more likely later in life, even without one specific trigger.

Learn About Hemorrhoid Symptoms

Early Signs and Symptoms You May Notice

Internal hemorrhoids often cause few or no symptoms at first. When symptoms do appear, the most common signs include:

• Bright red blood on toilet paper or in the toilet bowl
• A feeling of fullness or pressure in the rectum
• Mild itching or irritation from mucus discharge
• Tissue that slips out of the anus during or after a bowel movement, known as prolapse³

Rectal bleeding should always be checked by a doctor, since other conditions can cause similar symptoms.

Can You Still Have Bowel Movements With Internal Hemorrhoids?

Yes. Internal hemorrhoids do not block or prevent bowel movements. Most people with internal hemorrhoids pass stool normally, though straining can make symptoms like bleeding or discomfort worse. Softer stool and steady hydration can make bowel movements more comfortable while the area heals.

When to See a Hemorrhoid Specialist

Mild internal hemorrhoid symptoms often improve within about a week with fiber, water, and gentle activity. See a specialist if you notice:

• Bleeding that does not stop or keeps coming back
• Hemorrhoids that prolapse and do not retract on their own
• Pain or swelling that interferes with daily life
• Symptoms that last longer than one to two weeks despite home care

An experienced hemorrhoid specialist can confirm the cause of your symptoms and recommend a treatment plan suited to your case.

Can USA Hemorrhoid Centers Help?

USA Hemorrhoid Centers offers Hemorrhoid Artery Embolization (HAE), a minimally invasive, outpatient procedure that reduces blood flow to the arteries feeding the hemorrhoidal tissue. The procedure is typically completed in under an hour, and most patients return to normal activities quickly. An experienced interventional radiologist evaluates the grade and type of your hemorrhoids before recommending the right approach for you.

Learn About HAE