Casal's necklace is seen in deficiency of: September 2012: (A) Vitamin A deficiency, (B) Niacin, (C) Vitamin B12 deficiency, (D) Iron deficiency anemia
Answer is B. Ans: B i.e. Niacin The Casal collar or Casal necklace is a clinical sign in which there is erythematous pigmented skin rash in the distribution of a broad collar (dermatomes C3 and C4). It is seen in patients with pellagra.