Bleeding from the anus is a common symptom of internal hemorrhoids or anal fissure. However, there may be other causes.
"Colorectal cancer" is a type of cancer that forms in the large intestine, and many of them form in the rectum and sigmoid colon close to the anus. At the early stage, the cancer remains in the mucosal layer of the innermost part of the colon wall and the submucosa of the outer side. However, if it is left untreated, the cancer will progress. If it reaches the muscle layer, treatment will be difficult.
As with hemorrhoids, colon cancer causes bleeding from the anus or bloody stool. Therefore, it is more likely to be mistaken for hemorrhoids and initial symptoms are overlooked. If colon cancer develops at a site distant from the anus, the stool is still liquid, and therefore, even if bleeding occurs at the affected site, it may be mixed with the stool and not visible to the naked eye.
Bleeding from hemorrhoids is generally considered to be fresh blood while bleeding from colon cancer is considered to be dark red. However, if cancer develops near the anus, it is likely to cause bleeding of fresh blood, so self-judgment is dangerous. In particular, people with a long history of hemorrhoids tend to assume that bleeding is caused by hemorrhoids. Colorectal cancer was actually found among cases in which symptoms are not improved by using OTC drugs. Visit a hospital if bleeding persists.
A protuberance formed in the mucosa of the large intestine is called a "colonic polyp". There are various types of colonic polyps (including rectal polyps). If they are left, some of them may become cancer. Also, when a polyp becomes large, it is more likely to be cancer. If a polyp is found, it will be resected and examined pathologically.
Colonic polyps often cause no symptoms and are often found incidentally in some situations such as a medical examination. Particularly, bleeding in colonic polyps does not accompany pain and they are likely to be mistaken for internal hemorrhoids. So people with internal hemorrhoids need to be particularly careful. However, rectal polyps close to the anus may sometimes cause subjective symptoms such as bleeding and a feeling of incomplete evacuation.
An inflammatory bowel disease that often starts developing in the rectum and causes inflammation of unknown cause. The mucous membrane of the rectum becomes sore and the sore may gradually spread to the entire large intestine. If appropriate treatment is performed at an early stage, the symptoms will be relieved. However, characteristically, this disease is prone to relapse and difficult to completely cure.
"Ulcerative colitis" may cause bloody stool mixed with mucus due to bleeding from the inflammation site and may be mistaken for internal hemorrhoids. Symptoms such as diarrhea, abdominal pain, fever, and anemia are also observed.