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
English: pellagra, Alpine scurvy, mal de la rosa, mal rosso, maidism, mayidism, Saint Ignatius' itch