A preterm infant on oral zinc acetate for low serum zinc developed hyperzincemia (427 µg/dL) after zinc oxide ointment was started for diaper dermatitis that had become eroded. Serum zinc fell after the skin healed and both zinc products were stopped. It did not rise again when oral zinc alone was restarted. The ward pharmacist and physicians scored the reaction as definite (Naranjo 9). They attribute it to increased percutaneous absorption of zinc through barrier-impaired skin.
Key numbers
Serum zinc (µg/dL), by postnatal day (Fig. 1 and case text): 102 on day 28; 65 on day 49; 54 on day 77; 427 on day 93; 199 on day 105; 52 on day 114; 101 on day 128.
Oral zinc acetate hydrate was 2 mg/kg/d from day 56, raised to 2.7 mg/kg/d on day 95, stopped with the ointment after the day-105 result, and restarted at 2 mg/kg/d on day 116. Zinc oxide ointment was applied from day 86. Erosion was noted on day 93 and the skin was almost clear by day 100. The 427 µg/dL sample was drawn on day 93 and reported on day 95 by the external laboratory. A total of 40 g of ointment was dispensed over the period. Application amount and frequency were not recorded. Serum copper was 66 µg/dL on day 108, within the normal range. Serum iron was 74 µg/dL on day 77 and 88 µg/dL on day 105. No vomiting or diarrhoea attributable to hyperzincemia occurred. The discussion cites a Japanese series in which 8 of 17 infants given zinc oxide ointment for diaper dermatitis developed hyperzincemia, one with vomiting, over three-day courses.
Methods (brief)
The report was compiled retrospectively from the medical record by the ward pharmacist. Causality was assessed with the Naranjo scale. The ointment base contained white petrolatum, bleached beeswax and sorbitan sesquioleate. The authors describe it as more absorbent of exudate than simple zinc oxide ointment.
Evidence fitness
The case supports the statement that zinc from zinc oxide ointment can raise serum zinc in a preterm infant with eroded diaper dermatitis. The time course, with a rise under ointment, a fall as the skin healed, and no rise on oral zinc alone, is the authors’ main argument. Concurrent oral zinc acetate is a confounder, and the authors address it. The case says nothing about the lead or cadmium that zinc oxide carries. It is relevant to this category as evidence that the diaper-area barrier in a preterm infant can pass zinc from a zinc oxide product.
Limitations
This is a single case with no wound photographs and no recorded application amount. The English abstract says oral zinc was restarted on day 114. The Japanese text and Fig. 1 show day 116, which is used here. The discussion calls the course 17 days, but the stated start (day 86) and the stop after the day-105 result imply about 19 to 20 days. The Japanese title uses the term for newborn. The infant was about three months old postnatally when the ointment was used.
Related evidence
- Diaper Cream, ZnO-Based
- Zinc
- Influence of two vehicles for zinc oxide on zinc absorption through intact skin and wounds
- Skin Barrier Function in Infants: Update and Outlook
Update history
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