Hypersensitivity reaction in an infant fed hydrolyzed lactalbumin contained in a semielemental formula.

Following introduction of milk protein formula feedings, a 6-month-old male developed profuse, watery diarrhea progressing to shock, requiring cardiopulmonary resuscitation. Reinstitution of enteral feedings with a formula containing hydrolyzed lactalbumin (Travasorb STD) resulted in recurrence of diarrhea with fever. Intestinal and rectal biopsies showed only nonspecific inflammatory changes. He was discharged on an elemental formula (Vivonex). Twenty-three months later, while admitted for evaluation of hypophosphatemic rickets, immunologic testing using the lymphocyte migration inhibition factor (LIF) test demonstrated positive reactions, especially to alpha-lactalbumin (56% inhibition) and whole cow's milk (22%, normal of less than 20% inhibition). Skin tests revealed sensitivity to cow's milk and eggs. Soy formula also produced diarrhea and bloody stools. Protein hydrolysate formulas, touted as hypoallergenic diets, are useful in infants with intolerance to milk protein. This is the first documented case of an immunological reaction to the hydrolyzed whey protein, lactalbumin. Although protein hydrolysate formulas are effective treatment in most infants with milk protein intolerance, allergic reactions are possible. Caution and close observation should be exercised in immunologically sensitized infants rechallenged with any formula.