Diarrhea is one of the most common symptoms of digestive disease around the world, and the dehydration related to diarrhea can be a serious concern. In the United States, however, diarrhea is often a nuisance that arises suddenly and then goes away after a short time. Most people have had diarrhea many times, but it doesn’t always manifest in the same way. Sometimes it can be especially uncomfortable and cause a burning sensation that makes it an even less pleasant poop-related malady. But what causes burning diarrhea?

What Is Diarrhea?

Healthcare providers generally define diarrhea as having loose or watery bowel movements three or more times in a single day. However, just as people can have very different normal bowel habits, diarrhea may also present with different levels of frequency. The most common experience of diarrhea is acute diarrhea, an isolated incident that may span one or two days and then resolves on its own. Persistent diarrhea, on the other hand, can linger for several weeks and is often a sign of an underlying illness. Anything longer than a month is considered chronic diarrhea and is both disruptive to one’s quality of life and potentially dangerous.

As noted, diarrhea is a common gastrointestinal problem that is thought to affect over 100 million Americans each year of all age groups. While it is usually a relatively benign problem in the U.S., it is unfortunately one of the leading causes of death of children in underdeveloped countries that have poor sanitation systems and a lack of access to clean water. One of the most dangerous aspects of diarrhea comes from rampant fluid and electrolyte loss; in persistent and chronic diarrhea, the digestive system is unable to absorb sufficient water from eating and drinking. This fluid loss can lead to dehydration and a variety of other serious health problems.

Signs and Symptoms Related to Diarrhea

Diarrhea is itself a gastrointestinal symptom characterized by passing loose or watery stool, but it can sometimes be associated with a number of other symptoms. It is quite common, for instance, to experience abdominal pain, cramping, or bloating with diarrhea. Some people may also experience nausea and vomiting, and, depending on the underlying cause, it is possible to also develop a fever. In rarer cases, as with the type of gastroenteritis known as dysentery, symptoms may include rectal bleeding or mucus present in the stool. Another common characteristic of diarrhea in general is the sudden or urgent need to have a bowel movement.

Causes of Diarrhea

There are many conditions that include diarrhea as a symptom, but the basic cause is related to the function of the large intestine. When digestion is working normally, digested food that has made its way through the digestive tract is a mostly liquid substance. When it reaches the colon, the intestinal lining absorbs water and gradually forms the substance into soft, solid stool that can be easily passed through the rectum. If too much water is absorbed during this process, the stool becomes hard and dry and difficult to pass (constipation); if too little water is absorbed, very little—if any—solid material is formed and the result is diarrhea.

The underlying reasons for the change in bowel motility that can lead to diarrhea are numerous, and that is why it is known as a symptom for so many different gastrointestinal conditions. Below are some of the most common causes of diarrhea:

  • Bacterial infection: Food or water contaminated by bacteria can get into the colon and disrupt the normal process of absorbing water. Examples include Escherichia coli (E. coli), Salmonella, and Shigella.
  • Viral infection: Viral gastroenteritis is a common condition that can be caused by exposure to viruses like the norovirus and rotavirus.
  • Parasitic infection: Parasites like Giardia lamblia can enter the body through contaminated food or water in a similar way as bacteria or viruses.
  • GI diseases: Many gastrointestinal diseases include diarrhea as a symptom, often because of inflammation or damage to the intestinal lining. Examples include irritable bowel syndrome (IBS), celiac disease, and inflammatory bowel disease (IBD); the two main types of IBD are Crohn’s disease and ulcerative colitis.
  • Food allergies: Allergies to certain types of food can irritate the digestive tract and cause diarrhea and other symptoms. A common example is lactose intolerance, an allergic reaction to milk and cheese.
  • Medicine: The long-term use of medications like antibiotics can impact the beneficial gut bacteria of the microbiome in the colon; an imbalance in the concentration of these bacteria can potentially cause diarrhea or constipation.
  • Surgery: Surgery on any part of the digestive tract can sometimes cause a patient to develop chronic diarrhea or other symptoms.

    What Causes Burning Diarrhea?

    The causes noted above refer to diarrhea in a general sense, but what about when diarrhea also causes an uncomfortable burning sensation? One possible explanation is related to the digestive juices involved in digestion. When food is in the stomach, acids and digestive enzymes are released in order to help break down the food; additionally, another acidic substance called bile is added at the beginning of the small intestine. Normally these acids are neutralized by the time waste material enters the colon, but the increased bowel motility can leave those acids still intact and irritating by the time loose stool is passed through the rectum.

    Another possible explanation for burning diarrhea is due to the presence of partially undigested food parts that may be rough or large and cause small tears in the rectum and anus. Then when the acids described above pass through, the burning sensation can be intensified. The same effect can be observed after eating spicy foods. Most spicy foods contain an ingredient called capsaicin that can irritate skin and other body tissues. When someone has diarrhea, the capsaicin can also make it to the end of the digestive tract without having been neutralized and cause irritation in the delicate tissues of the anus. Below are some other possible causes of burning diarrhea:

    • caffeine
    • stress
    • artificial sweeteners
    • excessive alcohol consumption
    • fructose
    • overuse of laxatives

      Treatment Options for Burning Diarrhea

      The treatment for any type of diarrhea is dependent on the type (acute, persistent, or chronic), but most people can avoid it by avoiding food triggers, reducing alcohol consumption, and generally drinking plenty of water. For acute diarrhea, you can also take over-the-counter (OTC) antidiarrheal medications or painkillers to treat some of the related symptoms. Additionally, increasing your daily dietary fiber intake is important both for avoiding diarrhea and overall health; this can be done by adding fiber-rich foods to your diet or taking fiber supplements. It is also important to take standard food safety precautions in terms of refrigerating and cooking foods to a proper temperature.

      When Should You Contact a Gastroenterologist?

      If you have persistent or chronic diarrhea, there may be an underlying condition that needs to be identified and treated by a gastroenterologist. At Cary Gastro, we are passionate about providing excellent digestive healthcare so that you can increase your quality of life. Diarrhea can be a difficult condition to manage, and can even be dangerous in some circumstances. If you would like to speak to our highly qualified and friendly staff, please contact us today to request an appointment.