NEET-PG 2021 — General Medicine

Q: A 45-year-old man presents with the following skin changes (as shown in the image). What relevant history should be taken to diagnose this condition?

History of dietary pattern, dementia, and diarrhea. ***History of dietary pattern, dementia, and diarrhea*** - The image displays skin changes consistent with a "Casal's necklace" pattern, characteristic of **pellagra**, a disease caused by **niacin (Vitamin B3) deficiency**. - Pellagra is classically associated with the "3 Ds": **dermatitis** (the observed skin changes), **diarrhea**, and **dementia**. A comprehensive history should therefore include questions about dietary patterns (especially corn-based diets lacking tryptophan and niacin), gastrointestinal symptoms like diarrhea, and neurological/psychiatric symptoms indicative of dementia. *Dementia* - While **dementia** is one of the classic "3 Ds" of pellagra (niacin deficiency), it is only one component of the presentation and insufficient on its own to guide a complete diagnostic history for this condition. - Focusing solely on dementia would miss crucial aspects like dietary intake and gastrointestinal symptoms that are integral to diagnosing pellagra. *Dietary history* - A **dietary history** is indeed very relevant for diagnosing pellagra, as it helps identify potential niacin deficiency, commonly associated with diets heavily reliant on corn without proper preparation. - However, pellagra is not only characterized by dermatological signs and dietary insufficiency but also by gastrointestinal and neurological symptoms. Limiting the history to diet alone would therefore be incomplete. *Depression* - **Depression** can be a symptom of various nutritional deficiencies and other medical conditions, but it is not one of the classic "3 Ds" of pellagra, which are dermatitis, diarrhea, and dementia. - While mood changes might be present in some patients with niacin deficiency, focusing solely on depression would not encompass the full clinical picture of pellagra and could lead to misdiagnosis. [Practice more General Medicine PYQs on OnCourse]

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A 45-year-old man presents with the following skin changes (as shown in the image). What relevant history should be taken to diagnose this condition?