Deficiency Causes deficiency in dietary intake due to storage in fat must occur over several months malabsorbtion fat-free diets Presentation night blindness xerophthalmia dry eye squamous metaplasia of corneal epithelium spots are known as Bitot spots follicular hyperkeratosis dry skin due to loss of sebaceous gland function frequent infections alopecia Excess Causes over supplementation regular intake > 15 x RDA consumption of wild game liver isotretinoin treatment Presentation arthralgias periosteal proliferation papilledema, seizures, headaches, nausea and vomiting result of intracranial swelling skin changes yellow pigment with excess β-carotene but sclera remain white contrasted with jaundice which sclera and skin turn yellow Teratogenic cleft palate, cardiac abnormalities a pregnancy test must be done before isotretinoin is prescribed for severe acne and the patient should use contraception if sexually active