Casal's necklace is a dermatological sign characterized by a necklace-like pattern of dermatitis typically seen around the neck. This condition is commonly associated with a deficiency of Niacin, also known as Vitamin B3. Niacin deficiency leads to a condition called Pellagra, which presents with symptoms such as dermatitis, diarrhea, and dementia. The specific pattern referred to as Casal's necklace occurs due to photosensitive dermatitis, which affects areas exposed to sunlight.
Among the given options, Niacin is the correct answer as it directly correlates with the deficiency causing Casal's necklace:
Deficiency
Condition
Vitamin A
Night blindness, xerophthalmia
Niacin
Pellagra (including Casal's necklace)
Iron deficiency anemia
Fatigue, pallor, dyspnea
Vitamin B12 deficiency
Megaloblastic anemia, neurological symptoms
Therefore, the correct answer is Niacin, because its deficiency directly results in Casal's necklace.
