Acute diarrhea is one of the most common health problems worldwide. It’s a type of diarrhea characterized by loose, watery stools that occur more frequently than normal. It typically lasts less than 14 days. While it can be uncomfortable and disruptive, most cases resolve on their own with proper care.

In this article, we’ll cover everything you need to know about acute diarrhea, from causes to treatment options.

What Is Acute Diarrhea?

Acute diarrhea involves having three or more loose or watery bowel movements per day. It usually starts suddenly and lasts less than two weeks. Most cases are caused by infections, though other factors can also trigger it.

The condition affects people of all ages but is especially common in young children. In developing countries, it remains a leading cause of childhood illness and death (1).

Common Causes of Acute Diarrhea

Understanding what causes acute diarrhea can help you prevent it and know when to seek treatment.

Viral Infections

Viruses are the most common cause of acute diarrhea, especially in children. Rotavirus is particularly significant, causing severe diarrhea in young children worldwide. By age 5, nearly every child will have had at least one rotavirus infection (1).

Other viruses that commonly cause diarrhea include:

  • Norovirus
  • Adenovirus
  • Astrovirus

Bacterial Infections

Bacteria can cause more severe diarrhea, sometimes with blood in the stool. Common bacterial causes include:

  • Enterotoxigenic E. coli (ETEC) – the most common bacterial cause in developing countries
  • Shigella – can cause dysentery with bloody diarrhea
  • Salmonella
  • Campylobacter

ETEC alone may cause about 280 million diarrhea episodes yearly in children under five in developing countries (2).

Parasitic Infections

Parasites like Giardia and Cryptosporidium can cause diarrhea, especially in areas with poor sanitation. These infections often last longer than viral or bacterial diarrhea.

Food and Water Contamination

Contaminated food or water is a major source of infection. This is particularly common when traveling to areas with poor sanitation, leading to what’s often called “traveler’s diarrhea.”

Medications

Antibiotics can disrupt the normal balance of bacteria in your gut, leading to antibiotic-associated diarrhea. This affects about one in five people taking antibiotics (3).

Symptoms of Acute Diarrhea

The main symptom is frequent loose or watery stools. Other symptoms often include:

  • Abdominal cramps or pain
  • Urgency to use the bathroom
  • Nausea and vomiting
  • Fever
  • Bloating
  • Loss of appetite
Warning
Seek immediate medical care if you experience severe dehydration, bloody stools, high fever (over 102°F), or signs of severe dehydration like dizziness, dry mouth, or decreased urination.

Risk Factors

Some people are at higher risk for acute diarrhea and its complications.

Age

Young children and elderly adults are most vulnerable. Children under 5 have the highest rates of diarrhea-related illness and death. In Sub-Saharan Africa, diarrhea prevalence in children under 5 was found to be 18.44% (4).

Living Conditions

Poor sanitation and lack of clean water increase risk significantly. Rural areas often have higher rates than urban areas. Households without improved water or toilet facilities have higher risks of diarrhea (4).

Weakened Immune System

People with HIV/AIDS, those receiving chemotherapy, or taking immunosuppressive medications are at higher risk for severe diarrhea.

Travel

Traveling to areas with different bacteria or poor sanitation increases your risk. Traveler’s diarrhea affects millions of international travelers each year.

Diagnosis

Most cases of acute diarrhea don’t require extensive testing. Your doctor will typically diagnose it based on your symptoms and medical history.

When Tests May Be Needed

Testing may be recommended if you have:

  • Severe dehydration
  • Blood in your stool
  • High fever
  • Symptoms lasting more than a few days
  • A weakened immune system

Types of Tests

When needed, tests may include:

  • Stool culture to identify bacteria
  • Stool examination for parasites
  • Multiplex PCR tests that can identify multiple pathogens at once

Modern multiplex tests can identify many different pathogens from a single stool sample, providing results more rapidly than traditional methods (5).

Treatment Options

The main goal of treatment is preventing dehydration and managing symptoms while your body fights the infection.

Oral Rehydration Therapy

Oral rehydration solution (ORS) is the cornerstone of diarrhea treatment. It contains the right balance of salt, sugar, and water to replace lost fluids and electrolytes. ORS has been shown to be as effective as intravenous fluids for most cases of dehydration (6).

Tip
You can make a simple ORS at home by mixing 6 teaspoons of sugar and 1/2 teaspoon of salt in 1 liter of clean water. Commercial ORS packets are also widely available.

Dietary Management

Continue eating as normally as possible during diarrhea. Avoiding food can actually slow recovery. Good food choices include:

  • Rice and rice-based foods
  • Bananas
  • Toast
  • Cooked vegetables
  • Lean proteins

Green bananas may be particularly helpful. Studies show they can reduce diarrhea duration and severity (7).

Probiotics

Probiotics are beneficial bacteria that can help restore gut balance. Several studies show they can reduce diarrhea duration by about 30 hours (8).

Effective probiotic strains include:

  • Lactobacillus rhamnosus GG
  • Saccharomyces boulardii
  • Lactobacillus reuteri

Zinc Supplementation

Zinc supplementation can reduce diarrhea duration and severity, especially in children. The World Health Organization recommends 20 mg of zinc daily for 10-14 days for children with acute diarrhea (9).

Medications

Anti-diarrheal Medications

Loperamide can reduce stool frequency and urgency. However, it shouldn’t be used if you have:

  • Bloody diarrhea
  • High fever
  • Suspected bacterial infection

Antibiotics

Antibiotics are only helpful for certain bacterial infections. They’re not effective against viruses and can sometimes make diarrhea worse. Your doctor may prescribe antibiotics if you have:

  • Severe symptoms
  • Bloody diarrhea
  • Confirmed bacterial infection
  • Weakened immune system

For traveler’s diarrhea, single-dose antibiotics can be effective. Azithromycin combined with loperamide has been shown to reduce symptoms quickly (10).

Prevention Strategies

Many cases of acute diarrhea can be prevented through simple measures.

Hand Hygiene

Regular handwashing is one of the most effective prevention methods. Studies show it can reduce diarrhea by 32% in community settings (11).

Water and Sanitation

Access to clean water and proper sanitation significantly reduces diarrhea risk. Interventions to improve water quality can be effective in preventing diarrhea (12).

Vaccination

Rotavirus vaccines can prevent severe diarrhea in children. These vaccines have been shown to reduce rotavirus hospitalizations by about 74% (13).

Food Safety

Proper food handling and storage prevent many cases of food-borne diarrhea:

  • Cook food thoroughly
  • Refrigerate leftovers promptly
  • Avoid raw or undercooked meats
  • Wash fruits and vegetables
  • Use clean utensils and cutting boards

Travel Precautions

When traveling to high-risk areas:

  • Drink only bottled or boiled water
  • Avoid ice cubes
  • Eat only thoroughly cooked foods
  • Avoid street vendor food
  • Consider preventive probiotics or antibiotics for high-risk travel

Complications

While most cases resolve without problems, complications can occur, especially in vulnerable populations.

Dehydration

Dehydration is the most common complication. Signs include:

  • Dry mouth and tongue
  • Decreased urination
  • Sunken eyes
  • Rapid heartbeat
  • Dizziness or lightheadedness

Electrolyte Imbalances

Loss of salts and minerals can cause muscle cramps, weakness, and heart rhythm problems. This is why ORS contains electrolytes as well as water.

Persistent Diarrhea

Sometimes acute diarrhea can become persistent, lasting more than 14 days. This may require different treatment approaches and further investigation.

Post-Infectious Complications

Some people develop irritable bowel syndrome after severe diarrhea. This has been particularly noted with certain bacterial infections.

When to See a Doctor

Most cases of acute diarrhea improve on their own. However, you should seek medical care if you experience:

  • Signs of severe dehydration
  • Blood in your stool
  • High fever (over 102°F or 39°C)
  • Severe abdominal pain
  • Diarrhea lasting more than 3 days
  • Frequent vomiting that prevents keeping liquids down
Note
Children, elderly adults, and people with weakened immune systems should see a doctor sooner, as they’re at higher risk for complications.

Conclusion

Acute diarrhea is common but usually manageable with proper care. Remember to stay hydrated, practice good hygiene to prevent spread, and seek medical care for severe symptoms.

With appropriate management, most people recover completely from acute diarrhea without lasting effects. Understanding the condition helps you take the right steps to feel better quickly and prevent future episodes.

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