Diarrhea: Your A-to-Z Guide from Diagnosis to Treatment to Prevention

More than 3 million young children die each year from diarrhea. Causes include change in diet, infection, antibiotic use, or a number of rare diseases.

Introduction to diarrhea:

Normal baby stool can look a lot like an adult’s diarrhea stool. Healthy baby poop is often soft and runny, and (especially in the first month) quite frequent. One 2-week-old with 10 runny stools a day may be perfectly healthy, while another 4-month-old with 3 stools a day, all firmer than the other baby’s, may have diarrhea. So how can a parent tell?

What is it?

When children lose more fluid and electrolytes in the stool than is healthy, they have diarrhea. It can be caused by a change in diet (including a change in mother’s diet if the baby is breastfed), by infection, by antibiotic use, or by a number of rare diseases. Each year there are about one billion cases of diarrhea in children worldwide. In most cases (more than 990 million of them), the diarrhea will resolve by itself within a week or so. Still, more than 3 million young children die each year from diarrhea (about 400-500 in the United States).

Who gets it?

Most children will have diarrhea several times throughout childhood. Most children with diarrhea have a viral infection in the gastrointestinal tract. Rotavirus, adenovirus, and the Norwalk virus are common causes. Bacteria, such as campylobacter or salmonella, and parasites, such as Giardia, can also cause diarrhea.

It hits hardest in children 3 to 24 months old, although it can happen at any age.

Viral diarrhea is most common between November and May in the temperate climates of the Northern hemisphere.

What are the symptoms?

Look for a sudden increase in the frequency of the stools. Each child has her own stool frequency pattern that changes slowly over time. If it changes noticeably within only a few days, she may have diarrhea.

Any baby who has more than one stool per feeding should also be suspected of having diarrhea, even if this isn’t a sudden change.
Also, look for a sudden increase in the water content of the stool. Other signs of illness in your baby, such as poor feeding, a newly congested nose, or a new fever, make the diagnosis of diarrhea more likely.

Is it contagious?

Most infections that cause diarrhea are quite contagious, spread by the fecal-oral route and by fomites.

How long does it last?

The duration will depend on the underlying cause. Diarrhea caused by antibiotic use may last as long as the child is taking the antibiotics.

An average diarrhea virus lasts for 5 to 7 days.

How is it diagnosed?

It is diagnosed by history, physical exam, and by examining the stool. If there is blood or pus in the stool, or if the diarrhea is not improving as expected, stool studies may be performed to determine the specific cause. These might include stool cultures, viral studies, and tests for parasites.

How is it treated?

The central concern with diarrhea is the possibility of dehydration from loss of body fluids. Treatment is aimed at preventing dehydration, the real culprit. Most children with diarrhea can be treated safely at home.

If your baby is breastfed, don’t stop. Breastfeeding helps prevent diarrhea (making diarrhea only half as likely) and it also speeds recovery. If your baby still seems thirsty after or between nursing sessions, you can supplement with an oral rehydration solution such as Pedialyte.

If your baby is formula-fed, you might want to switch to a soy-based formula while the diarrhea lasts. A soy formula containing fiber (Isomil DF) can be even more effective at slowing down the stool. Do not dilute the formula. As with breastfed babies, supplementation with an oral rehydration solution can help replenish the fluids and electrolytes that have been lost in the diarrhea stools.

If your baby is already big enough to be taking solid foods, carrots, rice cereal, bananas, potatoes, and applesauce can help slow down the stools. Avoid fruit juices, peas, pears, peaches, plums, prunes, and apricots until the stools are back to normal, which should be within a week or so.

Yogurt and other sources of beneficial bacteria can help to actively treat diarrhea from any cause.

If the diarrhea lasts longer than a week, or is accompanied by more than 72 hours of fever, get in touch with your pediatrician. Contact your pediatrician right away, however, if your baby won’t drink or appears to be getting dehydrated (dry mouth, crying without tears, sunken soft spot, lethargic, or going 8 hours without producing urine) or if your baby is under two months old and has diarrhea with a fever. Vomiting for 24 hours, 8 stools in 8 hours, or the presence of blood, mucus, or pus in the stool should also prompt a call to your pediatrician.

How can it be prevented?

Most diarrheas are infections spread primarily via the fecal-oral route. Invisible organisms from the stool hide on hands, toys, and surfaces. From there, they make it into someone’s mouth.

Children whose stool overflows diapers or toilets should be kept out of day cares and schools. General fecal-oral and fomite precautions also decrease the spread of diarrhea germs. Every child eventually gets some, but cleaning and hand washing can delay infections and make them milder and briefer.

Eating active culture yogurt or other sources of beneficial bacteria can also minimize diarrhea, especially diarrhea caused by antibiotics or infections.


Last medical review on: August 21, 2013
About the Author
Photo of Alan Greene MD
Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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