Can IBS cause blood in stools (rectal bleeding)?

Key takeaways

• IBS is a gastrointestinal disorder characterized by abdominal discomfort and change in bowel movement
• IBS does not typically cause blood in stool. However, IBS symptoms such as constipation can cause small tears in the anus leading to streaks of blood in a person’s stool.
• Speak with a doctor if you notice blood in your stool, as other underlying medical conditions can cause it. 

Irritable bowel syndrome (IBS) is a condition that affects the gastrointestinal system. It is one of the most commonly diagnosed gastrointestinal disorders.

Blood in stool, also called rectal bleeding, is not commonly seen in people with IBS. However, it is possible. 

If you have IBS and notice blood in your stool, you may have a minor injury in your anal canal due to passing hard stools (constipation) or stooling frequently (diarrhea), which are both common symptoms of IBS.

In this article, we will discuss IBS, factors causing blood in stool in people with IBS, signs and symptoms of IBS, and some other medical conditions that can cause blood in the stool. 

What is Irritable bowel syndrome?

As the name implies, irritable bowel syndrome (IBS) is a group of symptoms that manifests when your intestine is ‘irritated.’ It is a functional gastrointestinal disorder characterized by two major symptoms: abdominal discomfort (pain, bloating, fullness, and gas accumulation) and changes in bowel movements (diarrhea, constipation, or both). 

The symptoms occur due to abnormal contraction of the muscles of the GIT. When the contraction is weak and slow, it causes constipation, while diarrhea can occur when the contraction is strong and fast.

Health experts are not sure what causes IBS. However, some factors, such as abnormal intestinal muscle contraction, uncoordinated signals between the brain and the digestive system, and food intolerance, have been linked to it.

What causes blood in stool in people with IBS?

Factors that may cause blood in stool in people with IBS include:

• Anal fissure: This is a tear in the anal canal. Frequent passage of hard stools causes overextension of the canal and subsequent tear in the anus. Blood from the injury can appear as blood streaks on stools.
• Abrasions: They can also occur along the walls of the anal canal due to friction from constant stooling. This may result in traces of blood in stools. 
• Hemorrhoids: These are swollen veins in the rectum and anus. Frequent passage of hard stools and straining when stooling can cause the veins to swell (called hemorrhoids) and rupture. The ruptured hemorrhoids may cause blood in stools. Bleeding due to ruptured hemorrhoids is mostly seen in people with IBS-C.

Signs and Symptoms of IBS

The symptoms of IBS differ among individuals. It can range from mild to severe, but proper management can help relieve symptoms so they do not interfere with daily activities. The major symptoms of IBS include:

• Diarrhea
• Constipation
• Alternating diarrhea and constipation
• Abdominal pain
• Bloating
• Abdominal fullness
• Excess flatulence
• Food intolerance
• Fatigue
• Anxiety

Other medical conditions that can cause blood in stool

Studies have shown that blood in stool is one of the signs of impending health problems. Seeing blood in your stool indicates bleeding along the gastrointestinal tract. And if you have IBS, seeing blood in your stool may also mean you have another underlying medical condition.

Some other conditions that can cause blood in stool include:

Peptic ulcer

This is an open sore in the inner lining of the stomach and/or the upper part of the small intestine. When an ulcer occurs in the stomach, it is called a gastric or stomach ulcer, and when it occurs in the upper part of the small intestine, it is called a duodenal ulcer. Severe peptic ulcers can cause bleeding, which can be seen in stool as brown tarry stains.

Inflammatory bowel disease (IBD)

This is an autoimmune condition that causes inflammation and damage to the walls of the GIT. It is of two types: Crohn's disease and ulcerative colitis. Both types of IBD can cause rectal bleeding.

Gastroenteritis

This is an infection of the gastrointestinal tract caused by a virus, bacterial, or parasite. This can cause damage to the walls of the tract resulting in rectal bleeding and blood in stools.

Polyps

These are benign growths on the lining of the digestive tract. Large polyps can cause rectal bleeding, which can be seen in stools.

Diverticulitis

This is a condition that occurs when small pouches develop on some part of the intestine. These pouches protrude through the walls of the intestine, causing bleeding.

Cancer

Cancer is the malignant growth of cells. Gastrointestinal malignancy causes growth in the lining of the tract and can result in bleeding in the GIT.

Is blood in the stool a cause for concern?

Blood in stool is one of the 'alarm signs' (signs indicating impending danger) of IBS and should be of utmost concern. It can be a sign of a minor injury in the gastrointestinal tract and can equally be a sign of severe health conditions, such as IBD or cancer. 

Early detection of these medical conditions helps make for a better outlook. Therefore, blood in stool is a good reason to go visit a primary care provider. If, after diagnosis, they find that you have a gastrointestinal condition, they may refer you to a gastroenterologist, a doctor that specializes in the treatment of gastrointestinal diseases. 

When to contact a doctor

Blood in the stool could be a result of a minor injury like an anal fissure and as well a sign of a more serious health condition. However, if you notice any trace of blood or large amounts of blood in your stool, you should consider seeing a doctor for a proper diagnosis to determine the major cause of the bleeding and commence treatment as soon as possible. 

This is especially necessary if the bleeding or blood in stool occurs for an extended period of time or is accompanied by other gastrointestinal symptoms.

Wrap up

Living with IBS can be burdensome for people with the condition, especially when the symptoms are severe and interfere with the activities of daily living. Nevertheless, following up with treatment and appointment dates with your doctor will help manage the condition. 

If you notice any sudden change in symptoms, such as worsening of the existing symptoms or development of new ones, e.g., rectal bleeding, you should consult your doctor as soon as possible for proper examinations and treatment.