Casal's necklace' is seen in the following disease: (A) Beri-Beri, (B) Scurvy, (C) Pernicious anemia, (D) Pellagra
Answer is D. The Casal necklace is an erythematous pigmented skin rash in the distribution of a broad collar (dermatomes C3 and C4). It is seen in patients with pellagra. It occurs as a result of niacin (vitamin B-3) deficiency. Pellagra is a disease characterised by diarrhoea, dermatitis and dementia. Ref : Biochemistry by U. Satyanarayana 3rd edition Pgno : 138-141