Anaphylactic shock due to cow's milk protein hypersensitivity in a breast-fed infant.

A newborn infant developed anaphylactic shock three times, once after ingesting his mother's milk and once after ingesting a formula containing casein hydrolysate. Symptoms resolved after cow's milk was withdrawn from the mother's diet and lactation was resumed. The case demonstrates that anaphylactic shock may occur in breast-fed infants and emphasizes the need to consider allergic phenomena even in these infants.