Pellagra is a vitamin deficiency disease (due to lack of niacin), often found in maize- or millet-dependent populations. A dermatitis, initially resembling sunburn, but followed by thickening, scaling, and pigmentation, is characteristic; internal epithelium is affected (sore tongue, diarrhea). Confusion, delirium, hallucination, and ultimately dementia may ensue. Niacin replacement is essential and food enrichment is an important preventative measure.