what does niacin deficiency cause

Niacin deficiency can cause a condition known as pellagra, which includes the triad of dermatitis, dementia, and diarrhea and can result in death. Pellagra is characterized by symptoms related to the skin, digestive system, and nervous system. These include thick, scaly pigmented rash on skin exposed to sunlight, swollen mouth and bright red tongue, vomiting and diarrhea, headache, apathy, fatigue, depression, disorientation, and memory loss. If not treated, pellagra can lead to death. Severe deficiency can also lead to cognitive decline such as memory loss and dementia.