<prompt> Casals paint necklace is caused byPellagraSLELichen planusPernicious anemia  <response>: Pellagra is characterised by deficiency of tryptophan, leading to photosensitivity on exposure to uv light three Dsof pellagra diarrhoea dermatitis dementia some impoant cutaneous features gauntlet of pellagra-sun burn over Dorsum of hands castles necklace- dermatitis over neck extending to anterior chest. cheliosis scarlet glossitis and stomatitis Ref Harrison20th edition pg 1345 