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Approximately half of all Americans experience hemorrhoids by the time they are 50 years old. A special variety of varicose vein, a hemorrhoid is an abnormally distended vein located either in the rectum or in the outer area surrounding the anal opening. When hemorrhoids occur internally, they often go unnoticed for a long time though they may produce some bleeding.

External hemorrhoids, however, are commonly associated with pain and itching as well as bleeding. Thus, most of the approximately 500,000 Americans who seek medical treatment for hemorrhoids each year are afflicted with the external type of the swollen veins. Only about one out of ten of these individuals have cases that require surgery. Much more frequently hemorrhoids are successfully treated with over-the-counter creams and suppositories, pain medications, cold compresses, and warm baths.

Hemorrhoids generally form due to excessive pressure in the rectal area, which causes the walls of nearby veins to distend as the result of an increased influx of blood. This increase in pressure may occur due to a variety of activities, such as straining during bowel movements, lifting heavy objects, sitting for extensive periods of time, and severe coughing. Also, pregnant women often experience hemorrhoids due to the intra-abdominal pressure caused by the presence of the growing fetus, and individuals suffering from chronic liver disease or tumors may experience them as a complication of their more serious condition.

Though usually considered a mild irritation, hemorrhoids can become a relatively serious condition in some cases. For instance, if an internal hemorrhoid is left untreated, it may swell to such an extent that it is forced outside of the anal opening, becoming what is known as a prolapsed hemorrhoid. This condition can be extremely painful and becomes even worse if the blood supply to the hemorrhoid is blocked by the sphincter muscle, resulting in a strangulated hemorrhoid. Another severe variety of hemorrhoid is the thrombosed hemorrhoid, which is characterized by rupture of the distended vein and the formation of a blood clot.