CODEs are rare genetic changes to a single gene that affects the lining of the intestine or changes to the immune system that also affects the cell function of important nutrient and electrolyte transporters in the intestine such as Cl−/HCO3− mutation.Otherwise, socioeconomic factors and access to treatment/healthcare play a significant part in developing chronic diarrhea as an infant. For instance, leading causes of chronic diarrhea in developing countries are infections of the intestine. In developed countries, chronic diarrhea has a diverse range of causes such as chronic infection of the intestines, autoimmune enteropathy, and inability to absorb nutrients via celiac disease, food sensitivities, etc.From age 0–30 days, typical causes are:
Abetalipoproteinemia, a condition caused by a genetic mutation that creates abnormal absorption of fats and some vitamins. Acrodermatitis enteropathica, a condition in which the intestine cannot absorb zinc. Autoimmune enteropathy, a rare condition in which the intestines are perceived as a foreign threat by the immune system and are attacked leading to irritation and inflammation. Microvillous inclusion disease, a condition caused by a genetic mutation leading to severe diarrhea because intestinal cells did not have normal development and thus the intestines are not able to absorb nutrients properly. Congenital chloride diarrhea, a lifelong condition caused by a genetic mutation that leads to diarrhea with a high concentration of chloride. Congenital sodium diarrhea, a genetic disorder caused by mutations in electrolyte transporters that disrupt the transport of Na+ across the intestine and results in high levels of Na+ greater than 145 mM in the stool.
Primary bile acid malabsorption, a gut defect in the reabsorption of bile acids in the small intestine which results in increased levels of bile acids in the colon leading to watery diarrhea and bloating. Chronic infection of C. difficile, G. lamblia
C. difficile - bacteria that can be the source of diarrhea. G. lamblia - a parasite that can be the source diarrhea.From 1–12 months, typical causes of chronic diarrhea are the following:

Acrodermatitis enteropathica, a condition in which the intestine cannot absorb zinc. Cystic fibrosis, a condition caused by a genetic mutation that can lead to injury to the bodys organs including the lungs and those in the digestive system. Apple juice and pear nectar, the digestive tract of children have difficulty absorbing significant quantities of sugars and carbohydrates which certain fruit juices can have. Celiac Disease, a disorder in which there is an immune response to eating gluten which can eventually cause damage to the small intestine over time and impedes absorption. Food allergy.Most instances of chronic diarrhea in infancy are caused by infectious and post infectious disease of the intestine as well as food sensitivities or allergies. Diagnosis
Diagnosis of toddlers diarrhea involves the evaluation of history of present illness, any relevant past medical history, and physical examination to determine any causative factors to inform treatment regimens and further recommendations.Evaluation of history of present illness includes:
Stool characterization (i.e. appearance, consistency, frequency, etc.) Time frame and duration (important for differentiation between acute and chronic diarrhea)
Food/drink allergies or restrictions (e.g. lactose intolerance)
Medications, especially antibiotics
Infection exposure (e.g.