"carcinoid syndrome (excess turnover of tryptophan, precursor of niacin, to serotonin (5-HT))"
"diarrhoea: intractable diarrhoea, stomatitis and glossitis"
"dementia: pellagrous encephalopathy may present as apathy, memory loss, disorientation, depression or delirium"
"malabsorption (e.g. Crohn disease)"
"drugs (e.g. isoniazid, ethionamide, 6-mercaptopurine, 5-fluorouracil, pyrazinamide, phenytoin, azathioprine, phenobarbitone)"
"drugs (e.g. isoniazid, ethionamide, 6-mercaptopurine, 5-fluorouracil, pyrazinamide, phenytoin, azathioprine, phenobarbitone)"