Pellagra is a nutritional disease due to a deficiency of the vitamin niacin and the essential amino acid tryptophan. The clinical features of pellagra are dermatitis, diarrhea, and dementia; it is commonly known as the “disease of the four Ds” because it is also fatal – the fourth “D” is death.
In alcoholics, it is not clear whether pellagra is the result of an impairment in tryptophan and niacin metabolism directly attributable to alcohol, or whether it reflects a general malnutrition in people who derive a significant portion of their energy needs from alcohol and therefore have a low intake of (nutrient-rich) foods.
