TABLE 1.

Etiologies for chronic diarrhea

Chronic infectious diseases

Bacterial and fungal infection (intestinal tuberculosis, Whipple's disease, Yersinia infection, histoplasma infection, cap polyposis, small intestinal bacterial overgrowth, and so forth), parasitic infection (amebic colitis, Giardia lamblia, Strongyloides stercoralis infection, cyclospora infection, and so forth), viral infection (cytomegalovirus infection, AIDS enteritis, and so forth).

Inflammatory bowel diseases

Crohn's disease, ulcerative colitis, eosinophilic gastroenteritis, Behçet's disease, celiac disease, diverticular‐associated colitis, radiation colitis, and so forth.

Neoplasms

colon cancer, gastrointestinal malignant lymphoma, VIP oma, somatostatinoma, gastrinoma, and so forth.

Malabsorption syndrome

chronic pancreatitis, lactose intolerance, dumping syndrome, blind‐loop syndrome, pancreas cancer, and so forth.

Irritable bowel syndrome and functional diarrhea

Drug‐related diarrhea

Drug‐induced collagenous colitis (non‐steroidal anti‐inflammatory drugs, proton pump inhibitors, angiotensin receptor antagonists), ursodeoxycholic acid, lactulose, antibiotics, DPP4 inhibitors, immune checkpoint inhibitors, and so forth.

Others

Hyperthyroidism, diabetes mellitus, hypoparathyroidism, adrenal insufficiency, amyloidosis, alcohol consumption, bile acid diarrhea, post‐cholecystectomy, hypogammaglobulinemia, intestinal lymphangiectasis, short bowel syndrome, mesenteric ischemia, overflow diarrhea, microscopic colitis, and so forth.