Biotin deficiency during total parenteral nutrition: its clinical manifestation and plasma nonesterified fatty acid level.

We report a case of biotin deficiency developed in a 25-yr-old man with Crohn's disease who had been on total parenteral nutrition for more than 9 months. His cutaneous, ophthalmic, and neurologic manifestations were characteristic of this disease entity described in literature. In particular, the appearance of his face deserves to be called "biotin deficiency facies." After administration of biotin the low plasma nonesterified fatty acid level promptly returned to normal. This phenomenon may prove to serve as a convenient means for the purpose of detecting biotin deficiency.