Soybean Allergy in Cow Milk-Tolerant Infants

Abstract

Seven infants aged 2 to 6 months presented with vomiting, diarrhea, apathy, and shocklike state up to 2 hours after ingesting 100 to 200 mL of soy-based formula. The reasons for the administration of soy-based formula were atopic family history, atopic dermatitis, constipation, acute gastroenteritis, and Jewish dietary (Kashrut) laws; in only one patient was soybased formula given because of cow milk allergy. Three of the patients had a similar reaction on repeated inadvertent exposure to soy-based formula. Five infants tolerated humanized milk formula without any adverse events. In one infant an allergic reaction to humanized milk formula (generalized urticaria and vomiting) developed at age 8 months, up to which time he had been exclusively breast fed. Only one infant had a positive skin test to soybean. The two cow milk-allergic infants had a positive skin test to cow milk. Five infants underwent oral soybean challenges at age 12 to 24 months, all of which were negative. We conclude that soybean allergy may appear in cow milk-tolerant infants in the first months of life. These infants, including the two infants with IgE-mediated cow milk allergy, presented with gastrointestinal symptoms only, which is compatible with food-induced enterocolitis.