Case history
Case history #1
A 49-year-old man is admitted to hospital with mental confusion and disorientation. He has a history of chronic alcohol use disorder and has been admitted to hospital 5 times over the past 8 years. His sister reports that he has lost his appetite and has been unable to eat for a few days prior to hospitalisation. He is emaciated, confused, disorientated, and agitated because of hallucinations. He has delirium tremens and is markedly ataxic. Gastrointestinal symptoms include anorexia, diarrhoea, and vomiting. He has glossitis and skin lesions that appear as vesicles over the extremities. Eczema-like lesions around the nose and mouth, as well as desquamation and roughened skin over the hands, are also present. Neurological examination reveals gait disturbance and extrapyramidal rigidity. Laboratory tests indicate anaemia. His serum proteins are less than 6 g/L and LFTs show marked elevations of aspartate aminotransferase and alanine aminotransferase.[7] The urinary 2-pyridone/N-methylnicotinamide ratio was <0.5 (mg/g creatinine).
Case history #2
A 15-year-old girl with anorexia nervosa has been abusing laxatives and vomiting in addition to severely restricting food intake over a period of 8 months. Her BMI is currently 17 kg/m². She has erythema on sun-exposed areas, glossitis, and stomatitis. She also has nausea, occasional diarrhoea, paralysis of the extremities, and fatigue. In addition, she is suffering from anxiety and depression. The only notable laboratory findings reveal a decreased level of 24-hour urinary 5-hydroxyindoleacetic acid. She is given 150 mg of oral nicotinic acid (niacin), and within 48 hours her symptoms resolve.[8]
Other presentations
The classic cutaneous features of pellagra are not always evident in people with chronic alcohol use disorder. A study in 1981 noted the absence of dermatitis in 20 patients with longstanding alcohol use disorder and a neuropathological diagnosis of pellagra. A suggested explanation is that these individuals have limited exposure to sunlight and therefore may not develop the characteristic, photosensitive dermatitis.
Clinicians should consider the presence of vitamin B3 deficiency in patients with other vitamin and/or mineral deficiencies, particularly vitamins B2 and B6, because such deficiencies typically co-exist and may cause similar symptoms.[2]
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