Niacin (vitamin B3) deficiency, also known as pellagra, is a multisystem disease which involves the skin, gastrointestinal tract and central nervous system.
It use to be widespread until the early twenty century, but after fortification of flour with niacin it was practically eradicated in developed nations 1.
Pellagra can still be found in some conditions that lead to niacin deficiency, such as 1:
- malnutrition (homelessness, anorexia nervosa or severe co-morbid conditions)
- chronic alcoholism
- hemodialysis or peritoneal dialysis
- drugs (e.g. isoniazid, ethionamide, 6-mercaptopurine and oestrogens)
- carcinoid syndrome (excess turnover of tryptophan, precursor of niacin, to serotonin (5-HT))
Pellagra is classically characterised by the 4Ds:
- dermatitis: brown discolouration of the skin observed in sun-exposed areas
- diarrhoea: intractable diarrhoea, stomatitis and glossitis
- dementia: pellagrous encephalopathy may present as apathy, memory loss, disorientation, depression or delirium
- leading to death
History and etymology
The term pellagra derives from Italian: “pelle agra”, which means rough skin 1.