A case of acquired zinc deficiency due to low zinc concentration in maternal breast milk

The present case is a 9-month-old boy who was born after a pregnancy of normal gestation and who had normal birth weight. He was not a result of a consanguineous marriage and his older sister had not had similar symptoms in infancy. From the age of 7 months, vesicles appeared on his toes, and scaly erythematous plaques appeared on his face, the external genital region, buttocks and lower extremities. He simultaneously had persistent diarrhea and whitening of hair. He gained little weight. Because he was not able to take solid food, he was exclusively breast-fed. Examination showed a low serum zinc level. His mother's serum zinc level was normal, but the zinc level in her breast milk was low. Based on these findings, this case was diagnosed as having acquired zinc deficiency due to low maternal breast milk zinc concentration. After treatment with oral zinc sulfate, 30 mg once daily for two weeks, the infant's serum zinc level achieved a normal range. Skin eruptions, diarrhea and whitening of the hair were also improved. No recurrence has been observed after the cessation of oral zinc sulfate administration. We reviewed previous cases of acquired zinc deficiency due to low zinc concentration in maternal breast milk, with special consideration of the effect of oral zinc sulfate treatment.