About the causes of rectal bleeding in men

Updated June 13, 2017

There are many causes of rectal bleeding in men. Most of these diseases and conditions also cause rectal bleeding in women. There are, however, some causes that affect only males. Most instances of rectal bleeding, in both men and women, are not life-threatening and usually clear up without treatment. Other cases can be quite serious.

Features of Rectal Bleeding

Rectal bleeding occurs when blood passes through the anus, which is located just above the rectum. The two most common causes of rectal bleeding are haemorrhoids and anal fissures, both of which can be caused by constipation. Other causes include infections, diverticulosis, colon polyps, peptic ulcers, inflammatory bowel disease, lack of blood supply to the bowel and cancer of the colon or rectum. All of these conditions can cause rectal bleeding in men and women.

In men, rectal bleeding can occur as a result of treatment for prostate cancer. A commonly used treatment, external beam radiation, often causes complications to arise that lead to rectal bleeding. Gay and bisexual men are at much greater risk of developing anal cancer, which can cause rectal bleeding.

Identifying Rectal Bleeding

Rectal bleeding can present itself in several ways. It may first be noticed as bright red blood in or on the stool, maroon stools, black tarry stools, blood stains on the toilet tissue or blood in the toilet bowl. Pain may or may not be associated with rectal bleeding, depending on its cause. Blood may also be occult, or hidden, in the stool. Testing may be done on the stool to find blood that is not seen by the naked eye.

Anal Cancer and Rectal Bleeding

Although anal cancer is not a common cause of rectal bleeding, it tends to occur more frequently in men with weakened immune systems. Both the human immunodeficiency virus (HIV) and the human papillomavirus (HPV) increase the risk of anal cancer in men. Consequently, gay and bisexual men are more likely to develop anal cancer because they are more likely to have diseases associated with HIV and HPV.

Methods of Detection

Many instances of rectal bleeding stop without treatment and are not life-threatening. However, because rectal bleeding can indicate a serious condition, it is important to determine the origin of the bleeding. Typical methods of detection are by physical examination and review of the medical history, colonoscopy, anoscopy, flexible sigmoidoscopy, visceral angiograms, radionuclide scans, stool screening and blood tests.

Warning for Prostate Cancer Patients

Men who have been treated for prostate cancer need to be especially careful to determine the origin of any rectal bleeding. Radiation treatment often causes rectal bleeding, but that expectation should not interfere with finding and treating other conditions that might also be responsible for the bleeding.

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About the Author

Linda Hinkle has been a writer since 2004. She spent 29 years teaching mathematics in public high schools and now maintains a private tutoring practice. In addition to writing about education and parenting issues, she writes mathematics assessment and test prep items. Hinkle is a graduate of the University of Central Arkansas, where she earned a bachelor's degree in education.