Pellagra

- triad of Dermatitis, Dementia and Diarrhea
- caused by niacin deficiency
- redness, cracks, chronic thickening, dryness and pigmentation (Casal's necklace or collar)
- painful, red, raw tongue, glossitis and angular stomatitis can occur
- encephalopathy characterised by confusion, disorientation, hallucination and memory loss occur
- neurological manifestation involves CNS and spinal cord where posterior and lateral tracts may be affected
- pellagra may occur in isoniazid therapy, alcohol dependent patients, carcinoid syndrome, Hartnup disease