Malabsorption

Small bowel: celiac sprue, Whipple’s disease, tropical sprue, eosinophilic gastroenteritis, small bowel resection, Crohn’s disease
Lymphatic obstruction: lymphoma, carcinoid, tuberculosis, Mycobacterium avium complex (MAC), Kaposi’s sarcoma, sarcoidosis, retroperitoneal fibrosis
Pancreatic insufficiency: chronic pancreatitis, cystic fibrosis, pancreatic cancer
Bacterial overgrowth, eg, diabetes
Reduced bile salts: ileal resection, Crohn’s disease, postcholecystectomy
Strongyloidiasis