Pellagra: This condition, caused by niacin (vitamin B3) deficiency, classically presents with the three Ds: diarrhea, dermatitis, and dementia. However, glossitis (inflammation of the tongue) and jaundice can also be associated with pellagra, especially in the context of malnutrition or alcoholism. The combination of diarrhea, jaundice, and glossitis could point towards a nutritional deficiency, with pellagra being a prime suspect due to its direct link with niacin deficiency, which affects the skin, mucous membranes, and the gastrointestinal system.

Viral Hepatitis: Certain viral hepatitis infections (like hepatitis A, B, or E) can cause jaundice and, less commonly, gastrointestinal symptoms like diarrhea. Glossitis might not be a direct symptom but could be related to the overall systemic illness or secondary infections. The presence of jaundice strongly suggests liver involvement, making viral hepatitis a plausible diagnosis.
Alcoholic Liver Disease: This condition can lead to jaundice due to liver dysfunction. Diarrhea might be present due to malabsorption or direct alcohol effects on the gut. Glossitis could be related to nutritional deficiencies common in alcoholics, such as vitamin B12 or folate deficiency. The combination of liver disease and potential for malnutrition makes this a likely consideration.
Giardiasis: An infection caused by the Giardia lamblia parasite, which can lead to chronic diarrhea. While less common, it could potentially cause jaundice if the bile ducts are involved. Glossitis might be a secondary symptom due to malabsorption. This diagnosis is more likely in individuals with exposure to contaminated water or travel history.

Hemolytic Anemia: Conditions like autoimmune hemolytic anemia can cause jaundice due to the breakdown of red blood cells. Diarrhea might not be a direct symptom, but certain medications used to treat hemolytic anemia could cause gastrointestinal side effects. Glossitis could be related to anemia itself. This diagnosis is critical because it requires specific treatment to prevent severe complications.
Wilson's Disease: A genetic disorder leading to copper accumulation in the liver and other organs. It can cause liver dysfunction (leading to jaundice), neurological symptoms, and potentially gastrointestinal symptoms like diarrhea. Kayser-Fleischer rings and neurological symptoms are more specific signs, but the diagnosis should be considered to prevent irreversible liver damage.

Whipple's Disease: A rare, systemic bacterial infection (Tropheryma whipplei) that can cause malabsorption leading to diarrhea, weight loss, and potentially jaundice. Glossitis could be part of the systemic illness. This diagnosis is rare but should be considered in cases where common causes have been ruled out and the patient has a suggestive travel or exposure history.
Eosinophilic Gastroenteritis: A rare condition characterized by eosinophilic infiltration of the gastrointestinal tract, leading to symptoms like diarrhea, abdominal pain, and potentially jaundice if the bile ducts are involved. Glossitis might be a part of an allergic or systemic reaction. This diagnosis requires a high index of suspicion and specific diagnostic tests.