Zinc deficiency: specific scalp hair defects seen by scanning electron microscopy may provide a valuable new test

Zinc deficiency in man results in multisystem disease. It may be acquired or hereditary; the latter can be fatal if left untreated. Premature babies are particularly susceptible to zinc deficiency. Unfortunately no simple, reliable test for zinc status exists at present. Short, newly-emerging scalp hair samples from 3 classical cases of zinc deficiency all showed the same characteristic abnormalities when examined by scanning electron microscopy, i.e. straight, blunt tips bearing scales, unusually thick cuticular scales with jagged free-edges, and very fine longitudinal corrugations in individual scales. These abnormal features occurring together appear to be specific for zinc deficiency; they also varied in severity with marked variations in zinc status during follow-up studies. Due to the relative rarity of classic cases of zinc deficiency, it is not possible for one centre of our catchment size to conduct a preplanned study. However, if the present findings can be confirmed elsewhere, it is concluded that scanning electron microscopy of appropriately-selected hairs may provide a valuable new test for the diagnosis of zinc deficiency and for monitoring the response to zinc therapy.