Niacin deficiency
From IDWiki
Background
- Deficiency in the water-soluble vitamin B3
- Also known as pellagra
- Risk factors include:
- Resource-limited countries were diet is heavy in untreated corn or sorghum (India, parts of China, and Africa; in Mexico, corn is treated and pellagra is rare)
- Alcohol use disorder
- Complication of bariatric surgery
- Anorexia nervosa
- Malabsorption
- Can also be seen in carcinoid syndrome, prolonged use of isoniazid, and Hartnup disease
Clinical Manifestations
- Classic triad of photosensitive pigmented dermatitis, diarrhea, and dementia
- Causes symmetric hyperpigmented rash that looks like a sunburn, on sunexposed skin ("Casal necklace")
- Also: red tongue, diarrhea, vomiting, insomnia, anxiety, disorientation, delusions, dementia, and encephalopathy
Investigations
- Urinary N-methylnicotinamide or erythrocyte NAD:NADP ratio
- Not readily available
