Differential Diagnosis for Yellow Diarrhea

• Single most likely diagnosis
  • Giardiasis: This is a common cause of yellow diarrhea, especially in individuals who have recently traveled or been exposed to contaminated water. Giardia lamblia infection can lead to malabsorption and steatorrhea, resulting in yellow, greasy stools.
• Other Likely diagnoses
  • Viral gastroenteritis: Viruses such as norovirus and rotavirus can cause acute gastroenteritis, leading to yellow diarrhea. The color may be due to the presence of bile and the rapid transit of stool through the intestines.
  • Bacterial gastroenteritis: Bacteria like Salmonella, Shigella, and Campylobacter can cause yellow diarrhea, often accompanied by other symptoms like fever, abdominal cramps, and vomiting.
  • Malabsorption: Conditions like celiac disease, lactose intolerance, or pancreatic insufficiency can lead to malabsorption of fats, resulting in yellow, fatty stools.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Intestinal obstruction: Although less common, intestinal obstruction can cause yellow diarrhea, especially if the obstruction is partial. This is a medical emergency that requires prompt attention.
  • Inflammatory bowel disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic diarrhea, which may be yellow in color due to the presence of blood, pus, or bile.
  • Infectious colitis: Certain infections, such as Clostridioides difficile (C. diff), can cause severe, life-threatening colitis, which may present with yellow diarrhea.
• Rare diagnoses
  • Carcinoid syndrome: This rare condition, caused by a neuroendocrine tumor, can lead to yellow diarrhea due to the excessive production of serotonin and other hormones.
  • Whipple's disease: A rare, systemic bacterial infection that can cause malabsorption, weight loss, and yellow diarrhea.
  • Eosinophilic gastroenteritis: A rare condition characterized by eosinophilic infiltration of the gastrointestinal tract, which can cause yellow diarrhea, abdominal pain, and other symptoms.