A disease caused by deficiency of niacin ( Vitamin B3) or tryptophan (or by a defect in the metabolic conversion of tryptophan to niacin). It is characterized by gastrointestinal disturbances, erythema and nervous or mental disorders; You may seen it in untreated or inadequately treated carcinoid syndrome patients. The patient should receive an adequate niacin supplement (nicotinamide rather than nicotinic acid, since the latter causes flushing) and should avoid foods, agents, and activities that precipitate symptoms.
