5 Main Types of Diarrhea & What They Mean

Key takeaways:

• Most cases of diarrhea are benign and will go away on their own.
• See a doctor if you are running a fever or having bloody diarrhea.
• Dehydration can be a complication of untreated diarrhea.

Diarrhea is common for adults and children. Diarrhea is passing loose or watery stools at least three times daily. Often it’s mild and resolves in 12-24 hours.

Sometimes diarrhea indicates a more serious medical problem. Diarrhea can lead to dehydration. This is especially true in children and elderly patients. Diarrhea is first classified as either acute or chronic. Diarrhea is acute if lasting less than 14 days and chronic if lasting four weeks or longer.

Main types of diarrhea and their meanings

Let’s break down the different types of both acute and chronic diarrhea and their causes.

1. Acute watery diarrhea

Acute watery diarrhea (or secretory diarrhea) is the most common form of diarrhea seen and evaluated in doctor’s offices. This is due to either an infection of the diarrhea with either a virus, bacteria, or parasite. The list of these infectious agents is long, and your doctor will ask you many questions to narrow down the causes.

Knowing if blood is present is also helpful. If you remember, write down the foods you ate 24-48 hours before the diarrhea began. Recall if you visited a swimming pool or have recently traveled out of the country. Children in daycare are also prone to specific infections that cause diarrhea.

Your doctor will ask you these questions (and more) to direct treatment. After examining you, they may want to order a study of your stool. When a stool sample is collected, it is sent to the lab and evaluated for the presence of bacteria, white blood cells, and other agents to determine what may be causing your diarrhea. If it is determined that a virus is the most likely cause of your symptoms, your doctor may advise you to rehydrate and wait for the symptoms to improve spontaneously. If your doctor prescribes an antibiotic it is important to continue it for the duration prescribed, even if you begin to feel better.

2. Acute invasive diarrhea

Acute invasive (or inflammatory) diarrhea (or dysentery) is a form of acute diarrhea that leads to blood in the stools with or without mucus. This is a more severe form of diarrhea caused by certain kinds of bacteria. Associated symptoms often include abdominal pain and fever. If you have bloody diarrhea, please call your doctor for an appointment, or go to an emergency department. Acute invasive diarrhea does not get better spontaneously and will require antibiotics.

3. Chronic watery diarrhea

Chronic watery diarrhea is watery diarrhea lasting more than four weeks. While infection can cause this, other medical conditions cause chronic watery diarrhea. Alcohol abuse, malabsorption, lactose intolerance, medication side effects, celiac disease, and inflammatory bowel disease are all potential causes of this symptom.

If you are experiencing chronic watery diarrhea, please call your doctor for an appointment. You may be referred to a specialist for further blood work, stool sampling, and colonoscopy.

4. Chronic invasive diarrhea

Chronic invasive or inflammatory diarrhea is chronic diarrhea that presents with liquid loose stools with blood. This lasts for more than four weeks. While infectious agents can lead to chronic invasive diarrhea, there are other causes. Any disease that leads to inflammation of the small or large intestine can cause chronic invasive diarrhea. This list includes diverticulitis, inflammatory bowel disease, ischemic colitis, and certain tumors.

It is important to note if you have had weight loss, fatigue, fever, or if you experience symptoms at night. In this situation, it is possible that you will be referred to a specialist and may require a colonoscopy to determine the exact cause of your symptoms.

5. Chronic fatty diarrhea

Chronic fatty diarrhea, or steatorrhea, is the presence of increased fat in stools. This presents with frequent, foul-smelling, greasy, bulky stools lasting more than four weeks. They may be pale in color as well. The presence of fat in stools indicates trouble with fat reabsorption in the small intestines. Reabsorbing fat from your diet is a complex process that involves the pancreas, liver, gallbladder, and small intestines.

Diseases that affect any of these organs can lead to chronic fatty diarrhea. It is important to call your doctor if you think you have this symptom. You will probably be referred to a specialist for further evaluation and testing.

Read our guides on treating diarrhea for more.

When to see a doctor about diarrhea

Many times, diarrhea can be safely observed at home without cause for concern. Some situations should prompt a visit to your doctor’s office. Dehydration is a common complication of diarrhea that more often affects children and the elderly. Be sure to watch closely for the signs and symptoms of dehydration. These include dizziness, weakness, feeling faint, dry skin, cracked lips, dark urine, and muscle cramps.

Another important recommendation is to please consult your doctor before beginning over-the-counter anti-diarrheal medication such as loperamide. Certain forms of infectious diarrhea can be made worse by these medications, and this can lead to serious complications.

Finally, wash your hands with soap and water if you are experiencing or caring for a patient with these symptoms. Even if the diarrhea itself is not due to an infection, other bacteria live in the stool and can spread to others.

You should see a doctor if:

• The diarrhea has lasted longer than 48 hours.
• The symptoms are so severe you cannot complicate normal tasks of daily living.
• You are experiencing a fever (temperature greater than 100.4 degrees Fahrenheit).
• You notice bloody or dark-black (tarry) stools.
• There are signs of dehydration.
• If you have recently taken antibiotics and are experiencing diarrhea.

You should go to the emergency room if:

• You are experiencing severe abdominal pain.
• You have not made any urine in the last 6 hours.
• The patient is confused or having difficulty staying awake and alert.

Questions to ask your doctor about diarrhea

• What do you think is the cause of this diarrhea?
• Is it safe to take over-the-counter medications to control the symptoms?
• How long do you expect this to last?
• When should I call you back if I don’t think I’m improving?

Managing diarrhea

Diarrhea is a common experience for adults and children alike. Many times it will resolve after 24-48 hours without serious complications. If you are unsure whether or not to be seen, go ahead and call your doctor and ask.

General Medicine follows a strict editorial process, including using real experts to write our articles, vetted primary sources, fact-checking, a secondary medical review, and updates as necessary. This article was medically reviewed and fact checked by Dr. Lane Thaut, DO.

Sources

Guerrant, Richard L., et al. "Practice guidelines for the management of infectious diarrhea." Clinical infectious diseases 32.3 (2001): 331-351.

Nemeth, Valerie, and Nicholas Pfleghaar. “Diarrhea.” PubMed, StatPearls Publishing, 21 Nov. 2022, www.ncbi.nlm.nih.gov/books/NBK448082/.

Akhondi, Hossein, and Kari A. Simonsen. “Bacterial Diarrhea.” PubMed, StatPearls Publishing, 2020, www.ncbi.nlm.nih.gov/books/NBK551643/.

‌Descoteaux-Friday, Garrett J., and Isha Shrimanker. “Chronic Diarrhea.” PubMed, StatPearls Publishing, 7 Aug. 2023, www.ncbi.nlm.nih.gov/books/NBK544337/.

‌Azer, Samy A, and Senthilkumar Sankararaman. “Steatorrhea.” Nih.gov, StatPearls Publishing, 21 Jan. 2020, www.ncbi.nlm.nih.gov/books/NBK541055/.