Pseudoacrodermatitis enteropathica due to transient zinc deficiency

Acrodermatitis enteropathica (AE) is a autosomal recessive syndrome of zinc deficiency. It classically presents with triad of periorificial and acral dermatitis, diarrhoea and total alopecia, seen in only a small fraction of cases. Transient neonatal zinc deficiency (TNZD) due to mutation of SLC30A2 leading to a AE like presentation was reported recently in Clinical and Experimental dermatology journal.

A 4-month-old girl presented with a 1-month history of a rash on her lower lip, chin, neck and anogenital area. She was exclusively breastfed but had recurrent diarrhoea. On physical examination, well-demarcated, symmetrical erythematous scaly plaques were present over the lower lip, chin, neck, axillae, antecubital fossae and anogenital area. There was no hair loss.

Baseline investigations were normal. Serum zinc levels were low (< 1 μmol/L; normal range 11–24 μmol/L). Alkaline phosphatase, a zinc dependent enzyme, was also low (60 U/L; 90–448 U/L). On further investigation authors found that mother's breast milk had low zinc concentration. Genetic testing for the SLC39A4 mutation, found in AE was negative. The patient was started on zinc sulphate 3 mg/kg/day leading to rapid resolution of symptoms.

TNZD is a rare condition caused by mutation in the ZnT-2 zinc transporter gene SLC30A2, which is responsible for zinc secretion into breast milk. It affects only exclusively breastfed infants, usually presenting at 2–5 months of age. Due to low zinc stores at birth and a higher metabolic demand for zinc premature infants are more commonly affected.AE differs from TNZD in that presents after weaning in breastfed infants and soon after birth in formula-fed requires lifelong zinc supplementation

In conclusion TNZD is a rare dermatosis which presentation similar to AE which can be treated with zinc supplementation at 2–3 mg/kg/day and do not require life-long zinc supplementation.

Source- King NY, Gach JE. Transient neonatal zinc deficiency in an infant. Clin Exp Dermatol. 2021 Jun 18. doi: 10.1111/ced.14755. Epub ahead of print. PMID: 34142742.