Question

The image shows a skin finding on the neck (Casal's Necklace). What are the associated features of this deficiency disorder?

• A. History of diarrhoea & dementia associated with cognitive impairment
• B. Bitot's spots
• C. Angular stomatitis
• D. Loss of muscle coordination

Hint:

The necklace-like skin rash on the neck is a classic sign of a specific vitamin deficiency -- recall its systemic manifestations.

Answer 1

The Correct Option is A

Step 1: Identify the skin finding.
The image shows Casal's Necklace -- a pathognomonic sign of Pellagra, which is caused by Niacin (Vitamin B3) deficiency. It appears as a symmetric, hyperpigmented, scaly dermatitis around the neck in a necklace-like distribution, classically in sun-exposed areas.

Step 2: Recall the classic triad/tetrad of Pellagra.
Pellagra is remembered by the 4 D's:
1. Dermatitis: photosensitive, symmetrical, hyperpigmented rash on sun-exposed areas (Casal's Necklace on the neck, Gauntlet on hands)
2. Diarrhoea: due to inflammation of the gastrointestinal mucosa
3. Dementia: neuropsychiatric symptoms including confusion, disorientation, and cognitive impairment
4. Death: if untreated (this is the only photosensitivity syndrome where death is a cardinal feature)

Step 3: Evaluate the options.
- Option A (Diarrhoea + dementia with cognitive impairment): Correct -- these are part of the classic 4 D's of pellagra.
- Option B (Bitot's spots): Feature of Vitamin A deficiency, not pellagra.
- Option C (Angular stomatitis): Feature of Riboflavin (B2) or iron deficiency, not pellagra.
- Option D (Loss of muscle coordination): Feature of Vitamin B12 or Vitamin E deficiency (cerebellar ataxia/posterior column involvement), not pellagra.

Step 4: Treatment.
Pellagra responds to treatment with nicotinic acid (niacin) supplementation.