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Pellagra — RACP Adult Medicine MCQ

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ModerateGastroenterologyPellagraRACP Adult Medicine

A 60-year-old woman with poor dietary intake presents with a symmetrical photosensitive rash (pellagrous dermatitis) on sun-exposed areas, diarrhoea, and dementia. She has angular stomatitis and a beefy red tongue. What is the most likely nutritional deficiency?

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Correct answer: C — Niacin (B3) deficiency

The 3 Ds of pellagra — Dermatitis (photosensitive, Casal necklace), Diarrhoea, and Dementia — indicate niacin (vitamin B3) deficiency. Risk factors include alcoholism, carcinoid syndrome (tryptophan diverted to serotonin), isoniazid use, and malnutrition. A 4th D (Death) occurs if untreated. Treatment is nicotinamide or nicotinic acid supplementation.

Reference: eTG Nutrition – 2024 – Pellagra