Source : Webster's Revised Unabridged Dictionary (1913)

Pellagra \Pel"la*gra\ (p[e^]l"l[.a]*gr[.a]), n. (Med.)
   An erythematous affection of the skin, with severe
   constitutional and nervous symptoms, endemic in Northern
   Italy.

Source : WordNet®

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: {Alpine scurvy}, {mal de la rosa}, {mal
         rosso}, {maidism}, {mayidism}, {Saint Ignatius' itch}]