Question

A 45 year old man presents with the following skin changes (image showing hyperpigmented, thickened rash over the neck and chest in a photosensitive distribution). What relevant history will you take to diagnose this condition?

• A. H/o dietary pattern, dementia, diarrhea
• B. Dietary history
• C. Dementia
• D. Depression

Hint:

Recall the three D's of Pellagra and which historical features you need to elicit to confirm the diagnosis.

Answer 1

The Correct Option is A

Step 1: Identify the condition from the image description. The image shows a hyperpigmented, thickened rash over the neck and upper chest in a photosensitive distribution. This pattern is classic for Pellagra (the necklace-like rash is called Casal's necklace).

Step 2: Recall the full clinical triad of Pellagra. Pellagra is caused by Niacin (Vitamin B3) deficiency and presents with the triad of:
- Dermatitis: Photosensitive skin changes (as shown in the image)
- Diarrhea: GI involvement
- Dementia: Neuropsychiatric features

Step 3: Determine what history is most relevant. To diagnose pellagra, the clinician must inquire about all three components: dietary pattern (maize/corn-based diet, alcoholism, malabsorption), presence of diarrhea, and any cognitive or psychiatric symptoms (dementia). Therefore, history of dietary pattern, dementia, and diarrhea together form the most comprehensive and diagnostically relevant history.

Step 4: Why not just dietary history? Dietary history alone is insufficient because the diagnosis of pellagra requires confirmation of all three clinical features, not just the nutritional cause.

Conclusion: The correct answer is Option A -- H/o dietary pattern, dementia, diarrhea.