What Does Diarrhea Look Like In An Infant?

Diarrhea in an infant looks like sudden, frequent, watery stools that are noticeably more loose and numerous than the baby’s normal pattern. For a breastfed newborn, this can be tricky because their baseline stools are already soft and seedy. The key difference is a change from the baby’s usual routine, not just the consistency alone. If a baby suddenly produces stools that soak into the diaper, happen far more often than usual, and have a foul odor, that is a strong sign of diarrhea.

What Does Diarrhea Look Like In An Infant?

Infant diarrhea looks different from adult diarrhea because a baby’s normal stool varies so much by age and feeding method. In the first weeks of life, breastfed babies often pass loose, yellow, seedy stools several times a day. This is normal, not diarrhea. Formula-fed babies typically have firmer, pasty stools that are tan or brown in color.

True diarrhea in an infant means the stool is suddenly much more watery than usual and the frequency increases sharply. The stool may be green, yellow, or brown, and it often has a stronger, more unpleasant smell than normal. You may also see mucus in the stool, and in some cases, the diaper may leak because the stool is so liquid.

A useful way to think about it is to compare with the baby’s own baseline. If a baby who normally has one firm stool a day suddenly has five watery stools, that is diarrhea. If a breastfed newborn who normally has six soft stools a day continues having six soft stools, that is likely normal.

How Many Wet Diapers Are Normal Versus Diarrhea?

Normal stool frequency in infants varies widely depending on age and diet. In the first month, breastfed babies may pass stool after every feeding, which can be six to ten times a day. After a few weeks, some breastfed babies suddenly drop to one stool every few days, and that is also normal.

Formula-fed babies typically pass one to four stools a day in the early months. After solid foods are introduced, stool frequency often settles into a pattern of one to two stools a day, though some healthy babies go every other day.

Diarrhea is not defined by a specific number of stools. It is defined by a sudden increase in frequency combined with a dramatic increase in water content. If the stool is mostly liquid and the frequency doubles or triples compared to the baby’s normal pattern, treat it as diarrhea.

What Causes Diarrhea in Infants?

The most common cause of acute diarrhea in infants is a viral infection. Rotavirus, norovirus, and adenovirus are frequent culprits. These viruses irritate the lining of the intestines, causing fluid to pour into the bowel rather than being absorbed. Bacterial infections from contaminated food or water can also cause diarrhea, though these are less common in exclusively breastfed infants.

Another very common cause in babies under six months is a sensitivity to something in the diet. In breastfed babies, this can happen when the mother eats certain foods that pass into breast milk. In formula-fed babies, a sensitivity or allergy to the protein in cow’s milk formula can cause chronic loose stools.

Teething is often blamed for diarrhea, but the evidence for this connection is weak. The American Academy of Pediatrics notes that teething may cause mild fussiness and drooling, but it does not cause significant diarrhea. If a teething baby has watery stools, look for another cause, such as a viral infection.

Antibiotics are another cause. When a baby takes antibiotics, the medication kills off normal gut bacteria along with the harmful ones. This disruption can lead to loose stools that last until the bacterial balance is restored.

When Is Infant Diarrhea Dangerous?

The main danger of diarrhea in an infant is dehydration. Babies have small bodies and lose fluids quickly. A baby can become dehydrated within hours of severe diarrhea, especially if they are also vomiting or refusing to feed.

Signs of dehydration in an infant that require immediate medical attention include:

• Fewer wet diapers than usual — fewer than six wet diapers in 24 hours for an older infant, or a significant drop from their normal count
• No tears when crying
• A dry mouth or sticky tongue
• A sunken soft spot on the top of the head
• Sunken eyes
• Unusual sleepiness or difficulty waking
• Skin that stays tented when pinched and released slowly

Blood in the stool, a fever above 100.4°F in an infant under three months, or diarrhea lasting more than 24 hours in a baby under six months all warrant a call to the doctor. Diarrhea accompanied by severe abdominal pain, a swollen belly, or repeated vomiting also needs medical evaluation.

How Is Diarrhea Treated in Infants?

For most healthy infants with mild diarrhea, the main treatment is to keep feeding. Breast milk and formula provide the fluids and electrolytes a baby needs. Do not stop feeding a baby who has diarrhea. Continuing to nurse or bottle-feed is the best way to prevent dehydration.

Oral rehydration solutions such as Pedialyte can be used, but always check with a pediatrician first about how much to give and at what age. These solutions replace the electrolytes and fluids lost in diarrhea, but they should not replace regular feedings for more than a short period. Do not give plain water to an infant under six months with diarrhea, because water lacks the electrolytes the baby needs and can be dangerous in large amounts.

Anti-diarrheal medications are not safe for infants. Never give an infant over-the-counter diarrhea medicine such as loperamide or bismuth subsalicylate without explicit instructions from a doctor. These drugs can be harmful in young children.

No clinical guidelines currently exist for using probiotics in infants specifically to treat diarrhea, though some pediatricians recommend them. The evidence for probiotics shortening the duration of infectious diarrhea in children is promising but variable by strain. If you are considering a probiotic, ask your pediatrician which one might be appropriate.

When Should You Call the Doctor?

Call your pediatrician if diarrhea lasts more than 24 hours in a baby under six months, or more than 48 hours in an older infant. Also call if the baby has a fever, shows any signs of dehydration, or has blood or mucus in the stool.

Seek emergency care immediately if the baby is lethargic, has sunken eyes, has not urinated in six hours or more, or cannot keep any fluids down. These are signs of significant dehydration that may require intravenous fluids.

In a newborn under three months, any diarrhea with a fever of 100.4°F or higher is considered a medical emergency. Newborns have immature immune systems, and a fever in this age group requires prompt evaluation.

Can Infant Diarrhea Be Prevented?

Prevention depends on the cause. For viral diarrhea, good hand hygiene is the most effective measure. Wash your hands thoroughly after diaper changes and before preparing bottles or food. Clean and disinfect changing surfaces regularly.

The rotavirus vaccine is highly effective at preventing the most common cause of severe diarrhea in infants. This vaccine is given orally at 2 months, 4 months, and 6 months of age in the United States. Since its introduction, hospitalizations for rotavirus diarrhea have dropped dramatically.

If a breastfed baby has chronic diarrhea linked to something in the mother’s diet, eliminating the suspected food may resolve the issue. Common culprits include cow’s milk, soy, eggs, and wheat. Work with a pediatrician or a lactation consultant before making major dietary changes, because eliminating foods from a nursing mother’s diet can affect her nutrition.

If formula-fed babies have persistent loose stools, a pediatrician may suggest trying a different formula. Do not switch formulas without medical guidance, because the cause of the diarrhea needs to be identified first.