Niacin (vitamin B3) deficiency, also known as pellagra, is a multisystem disease that involves the skin, gastrointestinal tract and central nervous system.
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Epidemiology
Niacin deficiency was widespread until the early twentieth century, but after the 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 comorbid conditions)
chronic alcohol use
malabsorption
haemodialysis 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))
Clinical presentation
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.
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