A male preterm infant with cow's milk allergy to human milk fortifier showing only severe respiratory symptoms.

We report a male infant with a birthweight of 1,400 g at 29 weeks 2 days gestation diagnosed as having cow's milk allergy (CMA) due to human milk fortifier, who developed severe respiratory symptoms. The infant had no gastrointestinal symptoms; rather, the initial symptoms were apnea attacks and wheezing with a prolonged expiratory phase that progressed to severe ventilatory insufficiency requiring mechanical ventilation. Aggravation of his general condition, which appeared to be due to sepsis, was improved by temporary starvation and respiratory care, but he relapsed on the resumption of enteral feeding of his mother's milk with a human milk fortifier. As a result, this event was interpreted as a positive oral food challenge test. The infant resumed complete breastfeeding without the fortifier and has not relapsed since. Examination of his serial cytokine profiles from residual serum revealed that although interleukin-5 was not increased, interferon (IFN)-γ was increased, suggesting some relation between the time course of IFN-γ and the infant's eosinophil count. These findings may indicate that the involvement of IFN-γ is one cause of the onset of this disease.