Causes of Diarrhea in Infants

Infants may experience diarrhea due to a variety of common factors, including those related to breastfeeding and formula feeding. The primary causes are detailed below:

Causes Related to Breastfeeding

It is often observed that breastfed infants tend to have bowel movements after each feeding, a situation that usually persists until approximately two months of age. During this period, they may have more than six bowel movements a day. The stool of breastfed infants is typically soft or liquid in consistency, light yellow in color, and may contain small seed-like particles. This is a normal occurrence and typically not a cause for concern. Several common factors can lead to diarrhea in breastfed infants, including:

Dietary Influences: It is important to evaluate the mother’s diet to identify foods that could potentially cause diarrhea in the breastfed infant. Certain foods consumed by breastfeeding mothers may lead to allergic reactions in the baby, resulting in diarrhea. Some of these foods include chocolate, spicy foods, cow’s milk, caffeinated beverages, and those that produce gas.
Laxatives: Some breastfeeding mothers may resort to using laxatives during the nursing period. While stool softeners, mild fiber supplements, or bulk-forming laxatives are generally safe, stimulant laxatives can pass into breast milk and may cause diarrhea in the infant. Consulting a healthcare provider before using any type of laxative is recommended for nursing mothers.
Weaning: Introducing new foods during the weaning process can lead to gastrointestinal disturbances due to food allergies or sensitivities in infants. Cow’s milk is particularly known to trigger such reactions and potentially cause diarrhea. It’s important for mothers to note that most infant formulas are derived from cow’s milk. Additionally, infants weaned in areas lacking adequate healthcare and nutrition are at a greater risk for illnesses and infections, which can manifest as diarrhea.

Causes Related to Formula Feeding

For infants who are fed with formula, the frequency of bowel movements can range from once to eight times a day during the first week of life, often tapering to one to four times a day by two months of age. The stool of formula-fed infants can vary from yellow to dark brown and has a thicker consistency, similar to peanut butter, compared to breastfed infants. Various reasons can cause diarrhea in formula-fed infants, including:

Allergies: Newborns can develop diarrhea as an allergic reaction to certain infant formulas, especially those based on cow’s milk. The proteins in cow’s milk can cause allergies in some infants, and some infants may also react adversely to soy-based formulas.
Contamination: Infants may experience diarrhea due to contamination of formula, often resulting from improper storage or the use of contaminated water or powdered formula. Such contamination can lead to gastrointestinal upset.

Other Causes

Several general factors can also lead to diarrhea in infants, regardless of their dietary regimen. These include:

Food Poisoning: Diarrhea may occur due to ingestion of contaminated water or formula, or consumption of tainted foods, which may harbor bacteria or fungi. While the immune system can handle small amounts of bacteria, larger quantities can provoke a response leading to diarrhea and vomiting.
Gastrointestinal Infections: Infants can experience various gastrointestinal issues, potentially due to viral, bacterial, or parasitic infections. Commonly known as gastroenteritis, or stomach flu, these infections can result in diarrhea lasting up to ten days, with symptoms such as vomiting, fever, abdominal pain, and dehydration.
Lactose Overload: Infants may develop diarrhea due to lactose intolerance or functional lactase deficiency, leading to difficulties digesting lactose found in milk. This condition is common in the early weeks of life but may continue for several months in some cases.
Carbohydrate Malabsorption: This occurs when infants, especially those under four months, receive excessive quantities of carbohydrates before their digestive systems develop adequate enzyme levels to process them, resulting in diarrhea.
Vaccinations: Some infants may experience mild diarrhea following vaccinations, which typically resolves within a few days.
Teething: While teething itself does not cause diarrhea, infants may place contaminated objects in their mouths during this time, leading to infections and diarrhea.
Travel: Infants may experience travel-related diarrhea, often referred to as traveler’s diarrhea, primarily caused by exposure to E. coli in contaminated water in developing countries.
Antibiotics: Antibiotic use may result in diarrhea as a side effect, as these medications can disrupt healthy gut flora while targeting harmful bacteria. Diarrhea typically resolves after completing the course of antibiotics.
Medical Conditions and Metabolic Disorders: Rare medical conditions and metabolic or functional disorders can also lead to chronic or recurrent diarrhea in infants, impacting their growth or resulting in weight loss. Doctors may perform diagnostic tests if a healthy infant fails to gain expected weight. Some notable conditions include:
- Celiac disease, an autoimmune reaction to gluten found in wheat, barley, and rye.
- Chronic gastrointestinal inflammation, known as inflammatory bowel disease, including Crohn’s disease and ulcerative colitis.
- Irritable bowel syndrome (IBS).
- Cystic fibrosis, a genetic disorder affecting nutrient absorption.
- Zinc deficiency.
- Neuroendocrine tumors, which often originate in the gastrointestinal tract.
- Hirschsprung’s disease, a congenital disorder resulting from missing nerve cells in the colon muscles.
- Eosinophilic gastrointestinal disorders, characterized by elevated eosinophils in the gastrointestinal tract.

Summary of Diarrhea in Infants

Diarrhea is generally defined as a sudden increase in the frequency of bowel movements and a change in stool consistency to loose and watery. According to the World Health Organization (WHO), diarrhea can be characterized by the passing of watery stools at a rate of three or more times a day. It is essential to note that soft stools or those resembling paste do not qualify as diarrhea in infants. The duration of diarrhea in infants can range from a couple of days to several weeks, depending on its severity. Numerous factors can affect normal bowel movement frequency and consistency, primarily the infant’s age and feeding approach, whether breast or formula. A green stool in a well-nourished and growing infant is generally not concerning, as it can result from bile; however, white, mucous, or blood-tinged stools, or those that appear black, warrant medical attention.

There are two main types of diarrhea: acute and chronic. Acute diarrhea typically appears suddenly and lasts less than two weeks; it is a prevalent issue in infants and often resolves spontaneously without treatment. Conversely, chronic diarrhea may persist for over two weeks and often indicates an underlying health issue that requires treatment for the diarrhea itself. Addressing the root cause is essential for effectively managing chronic diarrhea.