<prompt> Casals Necklace is seen in deficiency ofVitamin AVitamin B3Vitamin B6Vitamin D  <response>: Pellagra Pellagra occurs due to Vitamin B3 Niacin deficiency Pellagra is characterized by by 4Ds : 1.Diarrhoea 2.Dermatitis 3.Dementia 4.Death. Skin rash in Pellagra may appear as pigmented and scaly in areas exposed to sunlight. Especially neck when it is known as Casals Necklace Ref: Park 25th edition Pgno : 657 Harrisons 15th edition Pgno : 463 