DefinitionPellagra is a disease that occurs when a person does not get enough niacin (one of the B complex vitamins) or tryptophan (an amino acid).Alternative NamesVitamin B3 deficiency; Deficiency - niacinCauses, incidence, and risk factorsPellagra is caused by having too little niacin or tryptophan in the diet. It can also occur if the body fails to absorb these nutrients. It may develop after gastrointestinal diseases or with Alcoholism.The disease is common in parts of the world where people have a lot of corn in their diet.SymptomsSymptoms of pellagra include:DelusionsDiarrheaInflamed mucous membranesMental confusionScaly skin soresReferencesBrust JCM. Nutrition- and alcohol-related neurologic disorders. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunde