What is pellagra? Pellagra is a disease that affects your digestive system, skin, and nerves, resulting in dermatitis, diarrhea, and mental disorders. The most common cause of pellagra is not having enough niacin (primary pellagra). Other causes of pellagra are associated with digestive disorders that reduce the absorption of niacin in your body. Niacin is also known as nicotinic acid, or vitamin B3. In the United States, individuals most at risk for developing pellagra are alcoholics, as a result of malnutrition. Both alcoholism and not consuming enough green vegetables, seafood, meat, and eggs commonly cause primary pellagra. Secondary pellagra occurs when sufficient niacin is consumed but not taken up and used by the body. Secondary pellagra is often caused by gastrointestinal diseases that prevent absorption of niacin. Because tryptophan is needed to make niacin, low levels of tryptophan may also lead to pellagra. The signs and symptoms of pellagra can be constant or occur periodically. Pellagra varies among individuals. Some people with pellagra have mild symptoms, such as fatigue, while others may develop severe depression and anxiety. Fortunately, pellagra can be treated with nutritional supplementation to resolve deficiencies in niacin. Lifestyle changes can reduce your risk for pellagra and include limiting alcohol intake, eating a well-balanced diet, not smoking, and always taking all medications and supplements as prescribed. In some cases, if left untreated, pellagra can lead to dementia, anxiety or depression that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have any of these serious symptoms, including altered mental status, alcohol withdrawal, or severe depression with suicidal thoughts. Seek prompt medical care if you are being treated for pellagra but mild symptoms recur or are persistent.