Bloody Diarrhea: 7 Causes & What to Do

Bloody diarrhea is usually caused by intestinal infections from viruses, parasites and bacteria. If left untreated, an infection can cause significant health consequences, like malnutrition and dehydration. 

In most cases, bloody diarrhea resolves on its own, but it is important to support your body with adequate hydration, a balanced diet and with medications as prescribed by your doctor. 

Bloody diarrhea can also be a symptom of other health conditions, like ulcerative colitis and intestinal cancer, or it can be a medication side effect. If you experience diarrhea with blood, you should monitor for the number of bowel movements you have, whether your stool is soft or liquid and how much blood is noted. You should se ea doctor for assessment to determine the underlying cause and initiate treatment as needed.

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The most common causes of bloody diarrhea include:

1. Rotavirus infection

A rotavirus infection is one of the most common causes of gastroenteritis and bloody diarrhea in babies and children under 5. This type of infection is usually contracted after consuming contaminated food or water. It is characterized by liquid or soft stools more tan 4 times per day. Some blood may be noticed in the stool, as well as a pus-like or mucus-like discharge. 

What to do: You should have the child assessed by a doctor. If possible, bring a dirty diaper or a picture of the stool so that the doctor can assess the stool color and amount of blood. Rotavirus can cause intense diarrhea with a very foul odor, and it can last for up to 14 days. During this time, the baby or child should be fed soups, pureed food and lean meats. It is very important to keep offering water, saline solution or coconut water after each loose stool to prevent dehydration.

Learn more about the causes and treatment of intestinal infections

2. E. coli infection

Escherichia coli, or E. coli, is a bacteria that is naturally found in the gut. It can often cause gastroenteritis in adults, and can lead to dysentery and intense abdominal pain.  

The type of E. coli that is normally found in the body is not harmful, however there are other types that can contaminate food and cause intestinal symptoms.

What to do: To relieve symptoms and prevent future flare-ups of gastroenteritis, you should have a healthy, balanced diet that is rich in probiotics. Probiotics help to maintain healthy gut health and prevent imbalances that can lead to illness. The doctor may prescribe antibiotics to combat harmful bacteria in the intestines. 

3. Shigella spp. infection

Another common cause of bloody diarrhea with mucus in adults is an intestinal infections with Shigella spp. bacteria. It is usually contracted following consumption of contaminated food or water. Symptoms of Shigella spp. infection can last for 5 to 7 days and can cause dysentery. Some children who become infected can even have seizures that resolve once treatment has started. 

What to do: In these cases, you should not take medication to stop the diarrhea, as they can worsen symptoms and stop bacteria from naturally being eliminated in the stool. You should consume plenty of water and foods that are easy to digest. The doctor may prescribe antibiotics depending on the microorganism tested. 

Check out these home remedies for an intestinal infection that you can use alongside your medical treatment. 

4. Inflammatory bowel disease

Inflammatory bowel diseases, like ulcerative colitis and Crohn’s disease, are characterized by chronic diarrhea that can contain blood or mucus, and cause intense abdominal pain, especially after eating. The causes of these illnesses are still not known, and they can emerge at any age. Symptoms often flare-up and then go into remission for periods of time. Tests that confirm the diagnosis of these diseases include a barium enema, a colonoscopy and a CT scan. 

What to do: Treatment for ulcerative colitis involves the use of medications that stop diarrhea as well as dietary supplements. In serious cases, in which intestinal inflammation is extensive and does not improve with treatment, surgical removal of parts of the intestine may be necessary. 

Patients are also advised to consult a registered dietitian to learn which foods are best to prevent further flare-ups and which foods to consume to prevent nutritional deficiencies. 

5. Intestinal parasites

A parasitic infection can cause bloody diarrhea in both children and adults, especially when there is a high load of parasites. Bloody diarrhea from a parasitic infection is more common in areas with less hygienic conditions and basic sanitation, where people are more likely to walk barefoot and consume contaminated foods. These infections are associated with symptoms like abdominal bloating, abdominal pain and loss of appetite. 

Read more about the symptoms of intestinal infection caused by worms and other parasites. 

What to do: If you suspect a parasitic infection, the doctor can order stool testing to confirm the presence of parasites. Treatment with medication can be started to fight off and eliminate the infectious parasites.

You should also maintain adequate hygiene habits and consume probiotic foods that can restore balance within the gut to prevent new infections. Read more about probiotic foods that you can eat during treatment of a parasitic infection.

6. Medication side effects

Some medications, like antibiotics, can cause diarrhea as a side effect. It is even more significant in those who already have diarrhea and take antibiotics without a prescription. Antibiotics should always be prescribed, as taking the wrong antibiotic can increase bacterial resistance and lead to even more growth of harmful bacterial in the body. 

What to do: Antibiotics or other medication that cause bloody diarrhea should be discontinued as per the doctor’s direction. You should see your prescriber to discuss whether there is an alternative medication you can take.

7. Bowel cancer

Bloody diarrhea that is not associated with any of the above causes can be a sign of a tumor in the intestines or abdominal cavity. To determine whether cancer is causing blood in the stool, the doctor will likely order various tests, like a colonoscopy. 

What to do: You should seek medical attention if you suspect cancer. Treatment often involves surgery, radiation therapy and/or chemotherapy. Be sure to know the signs of cancer to monitor for. 

Other causes

Other, more severe, causes of bloody diarrhea include bowel obstruction, poisoning or significant abdominal trauma. All of these require urgent medical attention, as symptoms are very intense and can be life-threatening. 

Radiation therapy in the abdominal area can also cause bloody diarrhea as a side effect. In this case, you should notify the doctor so that the diarrhea can be addressed. Many patients are prescribed supplements to maintain gut health as well as medications to stop diarrhea.

When to see a doctor

Bloody diarrhea is not always a significant finding, especially when it is an isolated incident. It can also be common in people with a history of hemorrhoids and constipation. However, you should see a doctor if you present with any of the following: 

  • More than 3 episodes in one day or within the same week
  • Fever over 38.5ºC (or 101.3ºF) or chills 
  • Bloody or very dark vomit 
  • Intense abdominal pain
  • Fainting
  • Difficulty breathing
  • A firm abdomen that is uncomfortable to palpate
  • If you have a weakened immune system due to a history of AIDS or cancer or example 

Bloody diarrhea can lead to complications like dehydration, iron deficient anemia, changes to kidney function or sepsis, which is a life-threatening condition. Therefore, a diagnosis should be confirmed promptly so that the right treatment can be started.