Laboratory for Molecular Diagnostics
Center for Nephrology and Metabolic Disorders


Diarrhea is the condition of at least three defecations each day.


The following classification is proposed:
(1) acute - less than 14 days in duration
(2) persistent - more than 14 but less than 30 days in duration
(3) chronic - more than 30 days in duration


Fructose malabsorption
The ingestion of large amounts of fructose may induce diarrhea in patients with fructose malabsorption.
Glucose-Galactose Malabsorption
Diarrhea manifests within the first weeks of life and causes severe life threatening dehydration unless glucose and galactose are eliminated from the diet.
Histamine Intolerance
In patients with histamine intolerance diarrhea manifests after the ingestion of greater amounts of biogenic amines.
Lactase deficiency
In patients with congenital lactose intolerance, diarrhea manifests with breast feeding.
Adult type lactose intolerance
In patients with adult type lactose intolerance, diarrhea after the ingestion of milk and other lactose containing products becomes apparent with increasing age.
ATTR amyloidosis
Diarrhea and obstipation can alternate. They are the result of autonomous polyneuropathy.
Trehalase deficiency
Diarrhea in patients with trehalase deficiency manifests after the ingestion of greater amounts of trehalase, predominantly in young mushrooms.
Update: April 29, 2019