Pellagra

Question 1

Pellagra

Answer 1

Pellagra is caused by a deficiency of vitamin B3 (niacin).

Because of the large range of organs and tissues impacted by niacin deficiency, the clinical expression of pellagra is diverse. Pellagra is classically defined by ‘the three Ds’:-

Diarrhoea
Dermatitis
Dementia

The encephalopathy resulting from niacin deficiency classically causes dementia but is also known to cause depression, mania, and psychosis (so called pellagra psychosis).

Alcoholics are particularly predisposed to niacin deficiency and hence pellagra but this is much less common than the Wernicke-Korsakoff syndrome (thiamine aka vitamin B1 deficiency).