A 42-year-old man with small-bowel fistula has been receiving TPN with standard hypertonic glucose-amino acid solution for the previous 3 weeks. The patient is noticed to have scaly, hyperpigmented lesions over the acral surfaces of elbows and knees, similar to enterohepatic acrodermatitis. What is the most likely cause of this condition? SELECT ONE.

Zinc is one of the metalloenzymes involved in lipid, carbohydrate, protein, and nucleic acid metabolism. Skin lesions similar to enterohepatic acrodermatitis are the most common signs seen in zinc deficiency. Other manifestations include hypogonadism, diminished wound healing, and immunodeficiencies. Copper deficiency is characterized by microcytic hypochromic anemia.