The consistency of a child's stool is related to how much water it contains. Loose stools occur when the water content in the stool is increased. A child's diet and a variety of illnesses -- including infections, inflammatory conditions and digestive disorders -- can lead to loose stools. Important considerations in narrowing the list of possible causes include the frequency bowel movements, the appearance of the stool, the child's diet, and whether there are other signs and symptoms present.
Infants -- especially if exclusively breast-fed -- normally have loose stools. Formula-fed infants typically have soft stools but those with a cow's milk or soy allergy may develop loose stools. Older children with other types of food allergies, such as to eggs, seafood or nuts, may experience loose stools as well. Diet also affects the consistency of toddlers' stools. Children who drink a lot of fruit juice or have large amounts of sugar in their diet from other food sources can develop loose stools, especially if their diet is also low in fat and fiber. This condition, known as toddler's diarrhea, typically resolves with a change in the child's diet. Children with lactose intolerance -- an inability to digest the natural sugar present in milk -- often experience gassiness, stomach pains and loose or watery stools when dairy products are eaten.
Infections of the digestive tract are a common cause of sudden-onset, loose stools in children. Viruses, including rotavirus and norovirus, are the most common culprits. While stools are often watery, they may just seem looser than normal with these infections. In some children, stools are initially watery but remain loose for a few weeks after the illness, until the bowels have fully recovered. Intestinal infections from consuming food or drinks contaminated with bacteria, such as E.coli, salmonella and shigella, can cause loose or watery stools. Parasites, which are a larger type of "bug" that can infect the digestive system, are another possible cause related to consumption of contaminated food or water. Infections outside the digestive system, such as a head cold or an ear infection, can also cause loose stools -- especially in young children.
Intestinal and Digestive Disorders
A variety of less common, intestinal and digestive disorders can cause loose stools in children. Crohn disease and ulcerative colitis, for example, are characterized by inflammation of the intestinal wall. These long-term conditions often cause loose or watery stools along with other symptoms, including abdominal pain and weight loss. Although most commonly diagnosed in adolescents and young adults, approximately one-quarter of cases are diagnosed in children. Celiac disease is another possible cause of loose stools and abdominal pain. The underlying problem with this condition is an immune system reaction to the food protein gluten, which is found in wheat, rye and barley. Hereditary disorders, such as cystic fibrosis, can interfere with normal digestion and the ability to absorb food also leading to loose stools.
When To See Your Doctor
Call your doctor right away if a child less than 6 months old has loose or watery stools, especially if there are signs of possible dehydration -- a dry mouth, no tears when crying, dry skin or a sunken "soft spot" on the top of the head. Also seek immediate medical care if your child has bloody diarrhea, abdominal pain, fever or frequent vomiting. Schedule a visit with your doctor as soon as possible if your child experiences frequent episodes of loose stool, especially if the child is failing to gain weight normally or is losing weight.