1. 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
   - pellagra, Alpine scurvy, mal rosso, maidism, mayidism, Saint Ignatius' itch

Type of: avitaminosis, hypovitaminosis

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