| pellagra | (n) a disease caused by deficiency of niacin or tryptophan (or by a defect in the metabolic conversion of tryptophan to niacin); characterized by gastrointestinal disturbances and erythema and nervous or mental disorders; may be caused by malnutrition or alcoholism or other nutritional impairments, Syn. mal rosso, Saint Ignatius' itch, mal de la rosa, Alpine scurvy, mayidism, maidism |