(BMJ) - A 16-yo girl presented with low body mass and skin changes around her neck. She was diagnosed with anorexia nervosa. The skin changes rapidly resolved within 72 h after nutritional supplementation. What is the cause?
Goiter (iodine deficiency)
Keshan disease (selenium deficiency)
Pellagra (niacin deficiency)
Scurvy (vitamin C deficiency)
Rickets (vitamin D deficiency)
You are correct. The patient had 'Casal's necklace,' a typical presentation of pellagra. It resolved with oral niacin replacement given as part of a vitamin B complex supplement. A goiter can be a sign of iodine deficiency, while selenium deficiency may cause a cardiomyopathy known as Keshan disease. Rickets is associated with bony deformities, while scurvy is associated with skin changes such as roughness, petechiae, and ecchymoses.