Hair, Nails, and Skin: Differentiating Cutaneous Manifestations of Micronutrient Deficiency.

Micronutrient deficiencies (MNDs) commonly lead to cutaneous abnormalities involving the skin, hair, and nails, and these cutaneous manifestations often provide clues to the existence of the underlying deficiency. MNDs may be present in at-risk individuals who have impaired absorption or poor dietary intake. The micronutrients that most commonly present with cutaneous findings include the B vitamins riboflavin, niacin, pyridoxine, biotin, and vitamin B12; vitamin C; the fat-soluble vitamins A, E, and K; the minerals zinc, iron, copper, and selenium; and essential fatty acids. This review will highlight the most common clinical hair, skin, and nail presentations associated with MNDs and an approach to their treatment.