definition of pellagra
Pellagra is a vitamin deficiency disease most frequently caused by a chronic lack of niacin (vitamin B 3 or synonym: vitamin PP (from: Pellagra Preventing factor)) in the diet.ellagra is a vitamin deficiency disease most frequently caused by a chronic lack of niacin (vitamin B 3 or synonym: vitamin PP (from: Pellagra Preventing factor)) in the diet.