Definition of Pellagra:

Pellagra is a disease that occurs when a person does not get enough niacin (one of the B complex vitamins) or tryptophan (an amino acid) in their diet. It can also occur if the body fails to absorb these nutrients.

The disease is common in parts of the world where people have a lot of corn in their diet. It is characterized by scaly skin sores, diarrhea, inflamed mucous membranes, mental confusion, and delusions. It may develop after gastrointestinal diseases or alcoholism.