Anal Bleeding – What Causes Anal Bleeding?

A person having anal bleeding passes blood from the anus, often mixed with stool or blood clots. It is also called as rectal bleeding because the rectum lies immediately above the anus. Although the blood may come out from the rectum, the bleeding can occur in any part of the gastrointestinal tract. In this article, we will discuss causes of anal bleeding.

Causes of Anal Bleeding:

Anal bleeding is a symptom of some other disease rather than a disease itself. Anal bleeding is seen in following conditions:

  • Hemorrhoids
  • Anal fissures
  • Colon polyps
  • Colon cancer
  • Ulcerative colitis or Crohn’s disease
  • Rectal cancer
  • Diverticulitis
  • Angiodysplasia
  • Infections
  • Gastrointestinal or small bowel lesion

Among all the above conditions,


are the most common cause of anal bleeding. Hemorrhoids are enlarged veins in anal area that rupture and oozes out bright red blood. In other mentioned conditions, the blood may appear in different colors, but it case of hemorrhoids the blood appears bright red as if blood oozed from a fresh cut on the finger.

Colorectal cancer is one of the most common of all cancers in the United States. Anal bleeding is the most prominent symptom of colorectal cancer. Any growths, either benign or cancerous, in the gastrointestinal tract occult bleeding at some point. This comes out from anus causing anal bleeding.

Inflammations and infections of gastrointestinal tract can produce extensive bleeding from the colon. Diverticular disease is no exception in which massive bleeding occurs. If the bleeding is too much, it indicates inflammation of or infection in the tract.

Blood thinning medications like warfarin may also cause anal bleeding as their side effects. Finally, old age abnormalities like angiodysplasia can also cause recurrent anal bleeding.

Diagnosis of anal bleeding:

Anal bleeding is a symptom. Approach to diagnosis is to know the underlying cause of the bleeding. Focus is to locate the site of anal bleeding. A complete history and physical examination are the vital parts of making a diagnosis.

Symptoms such as stool color and consistency, changes in bowel habits, the presence of pain or tenderness can give a clue. Seeing the presence of pain and tenderness, the doctor can pinpoint the affected area.

A blood count is done to see whether the person is anemic due to bleeding. It also gives an idea of the extent of the bleeding. Some medications and foods give bloody color to the stool. Blood count helps in ruling out those false signs.

Endoscopy is the most reliable technique to diagnose anal bleeding. It is used to diagnose many other abnormalities of gastrointestinal tract.

Endoscope is a flexible instrument that consists of a long, thin, flexible tube (sometimes it can be a rigid tube) which has a light and a video camera.

Depending on the site, endoscopy can be upper gastrointestinal endoscopy or lower gastrointestinal endoscopy. The doctor can see into esophagus, stomach, duodenum and upper part of small intestine in upper endoscopy. Lower small intestine, colon, rectum and anus can be seen in lower endoscopy.

A new diagnostic instrument called a capsule endoscope is also used to know the exact cause of anal bleeding. The capsule contains a tiny camera in the instrument that transmits images to a video monitor. This advanced technique is most often used to find the bleeding portions of the small intestine that are hard to reach with the conventional endoscopy.

Comments are closed.