<prompt> The triad of ;diarrhea, dementia, and dermatitis; is characteristically seen in the deficiency of vitamin ___RiboflavinNiacinThiaminePyridoxine  <response>: Niacin deficiency results in pellagra.The early symptoms are vague. Anorexia, lassitude, weakness, burning sensations numbness and dizziness may be prodromal symptoms, After a long period of deficiency, the classic triad of dermatitis, diarrhea and dementia appears. Ref: Page 182; Nelson textbook of pediatrics; 17th edition 