Derm: Pellagra: Free MSRA Podcast

🎧 FREE MSRA PODCAST – Pellagra (Niacin Deficiency)🧠 One of the most classic, exam-friendly conditions – but still clinically relevant today. Let’s break down pellagra, the disease of the 4 Ds:Dermatitis, Diarrhoea, Dementia, and Death.🧠 Key Learning Points📌 DefinitionPellagra is caused by a deficiency of niacin (vitamin B3) or its precursor tryptophan. Classically presents with the “4 Ds”:• Dermatitis• Diarrhoea• Dementia• Death (if untreated)📌 Causes🔹 Malnutrition – poor intake of niacin/tryptophan🔹 Alcoholism – poor diet + malabsorption🔹 GI disorders – e.g. Crohn’s, coeliac, chronic diarrhoea🔹 Drugs – especially isoniazid (blocks tryptophan → niacin pathway)🔹 Corn-based diets (niacin bound and non-absorbable unless nixtamalized)🔹 Carcinoid syndrome, Hartnup disease, and eating disorders🔹 Modern restrictive diets lacking niacin-rich foods📌 At-Risk Populations• People with alcohol use disorder• Individuals with malabsorptive GI conditions• TB patients on isoniazid• Elderly or undernourished• People on fad diets🧬 PathophysiologyNiacin is needed to form NAD and NADP, vital coenzymes in:• Energy metabolism• DNA repair• Steroid/fatty acid synthesis⚠️ Deficiency disrupts high-turnover tissues (skin, gut, brain)👀 Classic Clinical Features: “4 Ds”🟠 Dermatitis• Symmetrical, sun-exposed areas• Begins as erythema, becomes scaly and hyperpigmented• 🧠 Mnemonic patterns:– Casal’s Necklace: hyperpigmented neck rash– Gauntlet of Pellagra: hands/arms rash🟡 Diarrhoea• Chronic, worsens malnutrition• May cause weight loss, electrolyte imbalances🔵 Dementia• Broad: confusion, irritability, memory loss, depression• ⚠️ May progress to long-term cognitive decline if untreated⚫ Death• Late complication due to multi-system failure, infection, or severe malnutrition📋 Other Symptoms• Loss of appetite, vomiting, weakness• Glossitis, stomatitis, esophagitis, vaginitis• Neurological signs: seizures, paresthesia💡 Think: broad multi-system impact🔎 Diagnosis• Clinical suspicion + dietary history• Look for the 4 Ds + risk factors• 💉 Blood niacin levels = unreliable• ✅ Best tests = urinary metabolites:– 2-pyridone– 2-methylnicotinamide• 💊 NAD/NADP levels in RBCs may help💊 Management✔️ Start niacin replacement immediately• Preferred form: oral nicotinamide• Dose: 100–200 mg TDS• Better tolerated than nicotinic acid (avoids flushing)✔️ Encourage dietary niacin: meat, fish, eggs, fortified grains✔️ Address underlying cause (e.g. stop isoniazid or treat alcohol misuse)⏱️ Improvement often seen in 24–48 hours🧠 Differential Diagnoses• B12 deficiency – neurological overlap• Coeliac disease – diarrhoea/malabsorption• Psychiatric illness – mimics dementia• Zinc/other vitamin deficiencies – mucosal and skin symptoms📉 Prognosis & Complications✅ Treated early = excellent outcome❌ Untreated =• Worsening diarrhoea → dehydration• Infections via damaged skin• Irreversible dementia• Death📆 Long-term follow-up needed for at-risk groups📎 More MSRA Resources for Pellagra📝 Revision Notes:https://www.passthemsra.com/topic/pellagra-revision-notes/🧠 Flashcards:https://www.passthemsra.com/topic/pellagra-flashcards/💬 Accordion Q&A Notes:https://www.passthemsra.com/topic/pellagra-accordion-qa-notes/🚀 Rapid Quiz:https://www.passthemsra.com/topic/pellagra-rapid-quiz/🧪 Topic Quiz:https://www.passthemsra.com/quizzes/pellagra/🎓 Full Dermatology Course:https://www.passthemsra.com/courses/dermatology-for-the-msra/Hashtags#MSRA #MSRARevision #MSRAFlashcards #MSRAAccordions #MSRAQuiz #MSRAQandA #Dermatology #Pellagra #4Ds #VitaminB3Deficiency #Niacin #PassTheMSRA #NutritionInMedicine