<prompt> Phrenoderma is repoedly caused due to deficiency of:Vitamin DVitamin AEssential Fatty AcidRetinoic acid  <response>: Essential fatty acid deficiency may lead to Phrenoderma. It is characterized by rough and dry skin characterised by horny papular eruptions in the posterior and lateral aspects of limbs and back. Ref: Park, 21st Edition, Page 573. 