Illness or Infection
Viral illness, bacterial infection, or parasitic infection are the most common causes of diarrhea. Viral diarrheas and some bacterial diarrheas are typically short-lived and resolves on its own after a few days, though children need to be monitored closely for dehydration. Severe bacterial and parasitic infections usually require treatment from a physician. Especially common in children with complex medical issues is a bacterial infection called C. diff or Clostridium difficile, which causes particularly foul-smelling diarrhea.
Some children have erratic motility, which may include fast motility in the intestines, or intestinal spasms. These can lead to diarrhea, since the food or formula passes too quickly for water and nutrients to be absorbed.
Children who have had a pyloromyotomy or pyloroplasty, as well as some children who have fundoplication surgery, may develop dumping syndrome, in which food or formula is “dumped” too quickly into the intestines. This condition causes diarrhea and can also cause blood sugar fluctuations. Other surgeries on the GI tract, especially removal of any portion of the bowel, may also cause diarrhea.
In young children, a common culprit for diarrhea is diet. Children who are receiving too much fruit, fruit juice, sweeteners, or artificial sweeteners may have diarrhea. In addition, allergies and intolerances are common causes of diarrhea. Lactose intolerance is likely the most common, but children may be sensitive or allergic to almost any food or ingredient. Too much fiber can also lead to diarrhea.
Medications such as antibiotics frequently cause diarrhea. Sometimes this is due to the medication itself, and other times it is due to the effect of the medication on the good bacteria in the gut.
Inflammatory bowel diseases, including Crohn’s and colitis, also frequently cause diarrhea. Functional bowel disorders, such as irritable bowel syndrome, may also cause diarrhea or constipation.
Other medical conditions that often cause diarrhea include disorders that affect absorption such as cystic fibrosis, metabolic disorders, and endocrine or pancreas conditions.